NationalOpticalAstronomyObservatories

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NATIONAL OPTICAL ASTRONOMY OBSERVATORIES

Cerro Tololo Inter-American ObservatoryKitt Peak National Observatory

National Solar Observatory

La Serena, ChileTucson, Arizona 85726

Sunspot, New Mexico 88349

ANNUAL REPORT

July 1990 - June 1991

January 28, 1992

TABLE OF CONTENTS

I. INTRODUCTION

II. AURA BOARD

III. SCIENTIFIC PROGRAM

A. Cerro Tololo Inter-American Observatory (CTIO)1. The Late-Time Luminosity Evolution of SN 1987A2. The Most Distant Radio Galaxies 23. The Mystery of CN and CH Inhomogeneities in Globular Clusters 3

B. Kitt Peak National Observatory (KPNO) 41. Resolved Images of High Redshift QSOs: A First Look 42. The Colors of Galaxy Clusters and the Nature of "Dark Matter" 53. A Giant Ionized Gas Cloud Associated with 3C 294:

A View of Galaxy Formation? 6

C. National Solar Observatory (NSO) 71. Near Infrared Magnetograph 72. High-Precision Polarimetry 83. Magnetic Fields of Active Regions 94. Progress in Adaptive Optics at NSO/SP 95. NSO/SP "Adaptive Mirror" 116. High Velocity Wind from a T Tauri Star 127. Magnetic Field Measurements 12

IV. MAJOR PROJECTS 13

A. Global Oscillation Network Group (GONG) Project 13B. 3.5-Meter Mirror Project 14C. WIYN Project 15

V. GEMINI PROJECT 16

VI. INSTRUMENTATION 17

A. CTIO n1. Array Controllers 182. 4-m Prime Focus Corrector and Atmospheric Dispersion Correction;

Large Format Prime Focus CCD 183. CCD TV Acquisition Cameras 184. 4-m Telescope Seeing Improvements 195. Other Projects '9

B. KPNO 19

1. Fiber-Fed Bench Spectrograph 202. CCD Mosaic Imager 203. Four-Color Camera (SQUID) 214. Cryogenic Optical Bench 215. Infrared Developments for 8-m Telescopes 216. PHOENIX 21

C. NSO 22

1. Spectromagnetograph 222. He 10830 A Video Filtergraph/Magnetograph 223. Near-Infrared Magnetograph 224. High-/ Helioseismometer 225. Stellar K-line Filter 23

6. Solar-Stellar Cross Dispersion 237. McMath 4-m Upgrade Study 238. Adaptive Optics Systems 239. Correlation Tracker 24

10. One-Shot Coronagraph Upgrade 2411. Perkin-Elmer Computer System Replacement at NSO/SP 2412. Other Projects at NSO/SP 24

VII. CENTRAL COMPUTER SERVICES 25

VIII. PERSONNEL 26

A. CTIO Scientific Staff Changes 26B. KPNO Scientific Staff Changes 26C. NSO Scientific Staff Changes 26

IX. DIRECTOR'S OFFICE 27

APPENDICES

Appendix A: NOAO Technical Reports ListAppendix B: CTIO Publications ListAppendix C: KPNO Publications ListAppendix D: NSO Publications List

I. INTRODUCTION

This report covers the period 1 July 1990 - 30 June 1991.

The National Optical Astronomy Observatories (NOAO) consists of three major astronomical centerswhich are available for use by astronomers from the United States and around the world: Cerro TololoInter-American Observatory (CTIO), Kitt Peak National Observatory (KPNO), and the National SolarObservatory (NSO). CTIO, in northern Chile, at an elevation of 7,200 feet, is the national center forastronomy in the southern hemisphere for the United States. KPNO occupies a 6,900-foot-high site nearTucson, Arizona, and contains the largest single collection of optical telescopes in the world. NSOcombines facilities at 9,200-foot-high Sacramento Peak, New Mexico with the giant McMath and VacuumTower telescopes at KPNO, providing an international center for studying the Sun.

II. AURA BOARD

The Association of Universities for Research in Astronomy, Inc. (AURA), operates the National OpticalAstronomy Observatories under cooperative agreement with the National Science Foundation (NSF).AURA also operates the Space Telescope Science Institute (STScI) under contract with the NationalAeronautics and Space Administration (NASA). AURA has a total of twenty-one member universities.Each member university appoints one individual to serve on the AURA Board, which also includes thePresident of the Corporation and twelve Directors-at-Large.

III. SCIENTIFIC PROGRAM

A. Cerro Tololo Inter-American Observatory (CTIO)

1. The Late-Time Luminosity Evolution of SN 1987A

No event in nature is more violent and powerful than the death of a massive star in the form of a type IIsupernova. For the star, it is the end of a comparatively brief but brilliant life, or at least the transition toa more exotic state. For astronomers, it provides not only spectacular fireworks, but a unique testingground for theories of stellar evolution and explosion. SN 1987A, which appeared on 24 February 1987in the Large Magellanic Cloud, our Galaxy's closest neighbor, is the nearest and brightest supernova tobe discovered since the invention of the telescope. It has provided the opportunity of a lifetime forastronomers to study a type II supernova in unprecedented detail. Visible only from the southernhemisphere, SN 1987A has been extensively followed by CTIO staff and visiting astronomers during thelast four years, providing a truly unique observational record.

One of the most fundamental quantities in studying a supernova is the evolution of the so-called"bolometric" luminosity, which is simply the energy radiated over all wavelengths as a function oftime. To calculate the bolometric luminosity at any instant, it is necessary to sum the radiation emitted,from gamma rays to the far infrared, excluding any source that is not directly part of the prompt energyrelease from the material in the supernova, such as an echo or stars lying along the line ofsight. Observationally, the energy spectrum divides into two disjoint ranges, the "high-energy" flux dueto the gamma-ray lines and X-ray continuum, which can only be observed from satellite or ballooninstruments, and the ultraviolet-optical-infrared "uvoir" flux, which is mosdy accessible to ground-based

telescopes. This division also has physical meaning.The high-energy component effectively represents theenergy emitted directly in the radioactive decays of the newly synthesized nuclides, whereas the uvoircomponent is a measure of the thermalized energy derived from the same radioactive decays, or from othersources such as the initial shock wave produced by the explosion or a buried pulsar.

Using an extensive set of optical and infrared photometry, spectroscopy, and imaging observationsobtained at CTIO, N.B. Suntzeff, M.M. Phillips, J.H. Elias, and A.R. Walker, along with D.L. DePoy(Ohio State U.), have followed the temporal evolution of the uvoir bolometric luminosity of SN 1987Athrough day 1442 since the explosion began. These data show that for the first two years, the dominantenergy source for the supernova was the radioactive decay of approximately 0.069 solar masses of 56Ni,which was synthesized in the initial seconds of the explosion. The 56Ni, which has a half-life of only 6.1days, quickly decayed to 56Co, which itselfdecayed with a much longer half-life of 77.1 days to the stableisotope 56Fe. By day 1000, however, Suntzeff and collaborators found that another source of energybesides the radioactive decay of 56Ni (and 56Co) was needed to explain the slow leveling off of the uvoirluminosity decline. The most likely explanations for this behavior are 1) the radioactive decay of 57Co to57Fe (half-life of 271 days), 2) the energy of a buried pulsar, or 3) contamination due to an underlyinglight echo. Only the first alternative provides a good fit to the data at all times. The final "Fe/^e isotoperatio implied by the uvoir data is somewhat higher than the theoretical expectations, but Suntzeff andcollaborators were able to show that the observed upper limits on the hard X-ray emission of thesupernova are consistent with this value. Significantly, model fits, in which a constant energy source suchas a pulsar is included, are clearly inferior to the pure radioactive decay models. Consequently, there isstill no direct evidence that the explosion of SN 1987A left behind such an object.

2. The Most Distant Radio Galaxies

The physical study of galaxies at large look-back times is one of the most challenging and rapidlychanging areas of astrophysics. Radio galaxies are currently unique in that they are the only objects inwhich star light can be observed over a look-back time comparable to the age of the universe. Over thepast two years, P. McCarthy (Carnegie Inst, of Washington), W. van Breugel (Lawrence LivermoreNational Lab.), and V. Kapahi (Tata Inst, of Fundamental Research, India) have used the CTIO 4-mtelescope to conduct a spectroscopic survey of intermediate flux density radio sources in the southernhemisphere. The sources were selected in a manner that optimizes the likelihood of reaching redshifts of 2and larger, without introducing undue bias in radio properties. To date, McCarthy et al. have obtainedredshifts and spectrophotometryof thirty-five radio galaxies, fifteen of which have redshifts greater than 2,making this one of the largest samples of galaxies at cosmologically-interesting distances.

Radio galaxies at large redshift have properties that are remarkably different from present-day massiveelliptical galaxies. In particular, imaging observations have shown that many of the distant radio galaxieshave a characteristic multi-modal structure composed of roughly linear chains of high surface brightnessultraviolet continuum clumps distributed on scales of 10 to 100 kpc. The independent discovery in 1987by McCarthy et al. and Chambers et al. that these lumpy and elongated galaxies are closely aligned withthe ejection axes of their radio sources has dramatically changed our thinking regarding the evolution ofthese massive galaxies. This "alignment effect" occurs nearly exclusivelyat redshifts greater than or equalto 1. The giant emission line nebulae also found to be associated with these galaxies are likewise stronglyaligned with the radio source axes. This alignment extends to redshifts lower than the continuumalignment. The origin of these strong radio/optical correlations is unclear and has become the focus of anumber of recent theoretical investigations. Models seeking to explain the alignments have invokedstimulated star rormation, scattered light from an obscured quasar nucleus, and gravitational

lensing. However, recent high signal-to-noise spectroscopy ofradio galaxies with z - 2, published in 1989by Chambers and McCarthy, suggests that the ultraviolet light is dominated by massive stars, favoringmodels in which star formation is induced by radio sources.

While the origin of the strong starbursts observed in these objects is still unclear, multi-color photometryat the longest wavelengths available from the ground can be used to constrain the ages of the oldest stellarpopulation. The galaxies show a wide range of rest-frame UV to rest-frame visible colors, which can beattributed to either a range of ages, and hence formation redshifts, or as starbursts of varying amplitudessuperposed on a single generation old stellar population. Of particular interest are the reddest objects athigh redshift. An example is the galaxy 0156-252 whose redshift of2.02 was measured by McCarthy andcollaborators with the CTIO 4-m telescope in 1989. A fit to the broad-spectral energy distribution of thisobject implies a redshift of formation of at least five, and perhaps as large as twenty, depending on theevolutionary model used. These very red objects are quite rare, yet vitally important, in that they currentlyprovide some of the strongest constraints on the epoch of galaxy formation.

3. The Mystery of CN and CH Inhomogeneities in Globular Clusters

The chemical composition of thenumerous globular clusters in our galaxy varies from cluster to cluster. Ithas long been known, with one exception, that individual stars within a given cluster are remarkablyuniform in the abundance ratio between the heavier or metallic elements and hydrogen. In color-magnitudediagrams this uniformity explains the extreme narrowness of the giant branches. Early metallicitydeterminations based on the relative strengths of ultraviolet light, which can be significantly diminishedby metallic absorption lines, and of blue light, confirmed that a very small metallicity spread is generallyfound within a given cluster.

In 1973, R. Zinn (Yale U.), observing with the KPNO 2.1-m telescope, found that six out of twenty starsobserved in the cluster M92 showed abnormally weak CH ^.4300 molecular bands. In order to investigatethis apparent chemical inhomogeneity, J.E. Hesser (then at CTIO), and F.D. Hartwick and R.D. McClure(Dominion Astrophys. Obs.), used the CTIO 1.5-m telescope in 1976 to measure the strengths of theCN X4215 band in several stars in various globular clusters. Narrow band-pass filters centered on ^4215A and on a neighboring part of the continuum were used to measure photometrically the CNbands. Unexpected large differences were found among the stars in a given cluster. In follow up studiesby Hesser and various collaborators, it was found that the distribution of CN band strengths could bebimodal in a given cluster. The bimodality was confirmed in 1979 by J. Norris and K.C. Freeman(Mt. Stromlo Obs.). In 1978, J.E. Hesser (then at Dominion Astrophys. Obs.) was able to obtain lowresolution spectra of some eighty stars in the bright southern globular cluster 47 Tucanae with the CTIO1.5-m telescope. He found CN strength differences in stars in the upper part of the main sequence as wellas in the horizontal and giant branches.

This result was confirmed in 1983 by Hesser, in collaboration with R.A. Bell (U. of Maryland) andR.D. Cannon (Royal Obs., Edinburgh), with high resolution spectrograms obtained with the CTIO 4-mtelescope. Furthermore, in 1989, observations with the same telescope byG.H. Smith (STScI), Hesser, andBell showed that the CN A.4215 and CH X.4300 band strengths in 47 Tucanae were anti-correlated.

The elements C and N play a major role in the CNO thermonuclear cycle operating in the interior of astar. In the 12C cycle, nuclei are converted to 13C, and eventually to l4N. The net effect is to increase theabundance of 14N and to decrease the abundance ratio 12C/13C from a value close to 90 to about 3. Sucha low 12C/13C ratio was found in 1987 by CTIO observers J.A. Brown and G. Wallerstein (U. of

Washington). In 1980, N.B. Suntzeff (then at U. of California, Santa Cruz), observing with the LickObservatory 3-m and the KPNO 4-m telescopes, found no evidence for variation of the abundance ratio(C+NQ/H, although C and N appeared to be anti-correlated. These results strongly suggested that CNOprocessed material was present in the outer layers of some stars and was the cause of the CN and CHinhomogeneities. Subsequently, the following questions arose: Was this material the result of deep mixingbetween the thermonuclear and outer layers of individual stars or had it been processed prior to the starsformation? Could mass-transfers in stellar encounters explain the observations?

The deep mixing possibility, is supported by findings from several investigators that the C abundances andthe value of the 12C/l3C ratio decrease as a star evolves along the giant branch in a cluster's colormagnitude diagram. Additional support for this possibility was obtained by C. Pilachowski (KPNO) withthe KPNO 4-m telescope and by J.B. Brown, G. Wallerstein, and J.B. Oke (California Inst, of Tech.) withthe Palomar 5-m and the CTIO 4-m telescope. These investigators found that individual stars in each ofseveral clusters, whether CN'-strong or not, had the same net C+N+O abundance, as expected in materialthat has undergone CNO processing within a given star.

There is evidence that other processes are at work as well. In 1981, P.L. Cotrell (U. of Texas) and G.S. DaCosta (Yale U.), observing with the CTIO 4-m telescope, found an enhancement of Na and Al abundancesamong CN-strong stars in two clusters. These enhancements are not expected to result from CNOprocessing. Recently, M.M. Briley (U. of Texas), J.E. Hesser, and R.A. Bell obtained spectra often mainsequence stars in 47 Tucanae with the same telescope. Among these were stars appreciably fainter thanpreviously observed. Surprisingly, these stars show the CN bimodality although, in theory, no deep mixingshould occur in such unevolved stars. It is not clear whether primordial processes in the proto-clusterclouds explain these two results. Evidence suggesting that the environment of a star within a cluster mayplay a role, at least in part, is derived from observations that indicate there is a radial gradient in thenature of the CN bimodality in 47 Tucanae (J. Norris and K.C. Freeman at the Anglo Australian TelescopeObservatory). Stellar encounters, that should be more frequent towards the cluster's center and accompanymass exchange, can explain this result.

The considerable effort spent towards explaining the CN and CH inhomogeneities has produced strongevidence in favor of the role played by the CNO cycle and some evidence favoring the deep mixinghypothesis. Nevertheless, this may not be the only explanation. Further efforts may result in a betterunderstanding of how the clusters were formed and of the mixing mechanism in stellar interiors.

B. Kitt Peak National Observatory (KPNO)

1. Resolved Images of High Redshift QSOs: A First Look

Soon after their discovery, quasi-stellar objects were so named because their optical images wereunresolved and stellar in appearance. These objects have become familiar over the years, but in many waysthey remain as enigmatic as ever. They form the class of the most distant objects in the Universe andproduce the most energetic and explosive events ever seen. These two properties make an understandingof the nature of quasi-stellar objects essential to cosmology, general relativity, and high energy physics.Because these objects emit up to one hundred times the energy of all the stars in a normal galaxy fromregions a millionth the size of a galaxy or less, some extremely powerful and very concentrated form ofenergy generation is necessary. The only viable candidate at the present time is the gravitationalsingularity, or black hole. The formation of a black hole of sufficient mass to power a QSO is thoughtto occur during the late stages of the evolution of a self gravitating system. Therefore, the appearance of

QSOs at high redshift early in the evolution of the universe may require extraordinary and rapidevolutionary paths for these objects. Until recently, the only spatially resolved features associated withQSOs were the regions of extended radio emission associated with a subset of these objects. These radiofeatures were remarkably similarin nature to the less powerful radio emission arising from some ellipticalgalaxies. This similarity provided a tantalizing possible link between galaxies and QSOs, but their pointlike optical appearance seemed to preclude QSOs from being a special form of galaxy.

This situation has now changed due largely to the remarkable increase in sensitivity provided by state ofthe art detectors used at the KPNO telescopes. Using the KPNO 4-m telescope and a UV-flooded800 x 800 pixel CCD detector at the prime focus, T. Heckman and M. Lehnert (Johns Hopkins U.),W. van Breugel (Lawrence Livermore National Lab.), and G. Miley (Sterrewacht, Leiden) have obtainedspatially resolved images of fifteen QSOs, all lying at redshifts greater than or equal to 2.0. The resolvedimages are all seen in Lyman-a emission, with typical size of 100 kpc and a typical luminosity of If/4ergs/sec. All of these QSOs are associated with radio emission. The optical nebulae are usually elongated,with the axis of elongation being aligned with the radio emission, or asymmetric. In this regard, theseobjects are very similar to the population ofhigh redshift radio galaxies that has recently been discovered.Photoionization arguments suggest that the radio emission arises from small dense clouds. Theproductionand confinement of such clouds implies a gas cloud around the QSOs which contains up to 1012 solarmasses of gas. In six of the QSOs, the UV continuum is also resolved, having diameters of 40 to 80 kpc.This UV emission could arise from starlight in a host galaxy or from scattered QSO light. Although themechanism that gives rise to the QSO emission may be unique and still obscure, these observationsstrongly suggest that the underlying parent object may be a system of stars. This, in turn, provides verystrong boundary conditions on models for the "central engine" in these objects, since they must evolveout of a gravitationally bound stellar system. Consequently, the high redshift problem described abovebecomes even more severe. It is not clear that conventional cosmological models will allow enough timefor the formation of a galaxy, the evolution of a dense stellar core, and the final collapse to form theputative black hole.

2. The Colors of Galaxy Clusters and the Nature of "Dark Matter"

In 1933, F. Zwicky first pointed out a discrepancy between the velocities of galaxies in rich clusters andthe total mass of stars in these systems. Assuming that these clusters have reached equilibrium, thevelocity dispersions indicate much more mass than can be accounted for by conventional stellarpopulations in the member galaxies. The "Dark Matter" problem has grown from this first exposition intoa major area of astronomical activity, with non-luminous material apparently existing in many places,always provided that the assumption of virial equilibrium is correct. In fact, the currently fashionablecosmological models require most of the mass in the universe to be invisible, since these models are basedupon the assumption that just enough mass exists to gravitationally bind the universe. However, there isno direct observational evidence for this much matter. Current observational limits provide only a fewtenths of the required mass. Although the desire persists in many quarters for this dark matter to be in theform of exotic, unobserved particles, much of it could be in the form of baryonic matter. If so, thismaterial could be in the form of very low luminosity stars, which is a plausible outcome given the generalsteep slope of stellar mass functions in the low mass region.

An investigation of this possibility has been carried out by J. Uson (National Radio Astron. Obs.) andS. Boughn (Haverford College). Using the KPNO 1.3-m and 0.9-m telescopes, these astronomers haveobtained single-aperture and CCD photometry on and near the centers of distant (0.14 < z < 0.20), richAbell clusters. Four clusters (A910, A1413, A1763, and A2218) were measured in the B, V, R, J, and K

bands. These bands were chosen because they would reveal the presence of a large population of very lowmass stars. For example, if the dark matter were in the form of the faintest known stars, it would producea K-band luminosity comparable to that of the visible galaxies but contribute essentially nothing in theV-band. This would result in a clearly observable shift in the V-K color index from that seen in normalgalaxies. Uson and Boughn find no anomalous infrared emission from the galaxies in these clusters. Infact, their observations show that no more than five percent of the dark matter can reside in objects ofmass greater than 0.1 solar mass. This interesting result does not imply that the dark matter must be non-baryonic, but it does place constraints on the lower end of the mass function if the matter is baryonic andcondensed. For example, with a low mass cutoff of 0.004 solar masses (thought to be the minimumcollapse mass) and an upper limit of 0.75 solar masses, the power-law exponent of the differential massfunction must be greater than 2.4. In any case, it is clear that these new results place important constraintson galaxy formation and evolution models that seek to incorporate the dark matter in condensed form.

3. A Giant Ionized Gas Cloud Associated with 3C 294: A View of Galaxy Formation?

3C 294 is a high redshift (z = 1.786) radio galaxy belonging to a class of objects that has receivedconsiderable attention in recent years. These objects are steep spectrum double radio galaxies, all at largeredshift, which show a remarkable alignment of optical emission coincident with the axis of the radiosource. This optical emission is seen primarily in emission lines, but it is also present in the visiblecontinuum and in the infrared. The extent of the emission is comparable to that of the radio source(10-100 kpc). Its origin is thought to be linked in some way with the ejection of the radio emitting plasmafrom the active galactic nucleus. This morphology is not seen in comparable radio galaxies at low redshift,suggesting that evolutionary processes must be playing a crucial role. The detailed nature of this processis not yet clear. If the optical emission elongated parallel to the radio axis comes from starlight, then itis possible that a burst of star formation has been triggered by the passage of the radio jet through thecircum-galactic medium. Since this is not seen in low redshift radio galaxies, it would imply that the gasaround high redshift galaxies may be extremely dense compared to that found in the present epoch. Evenif the light is not primarily from stars, the presence of emission lines implies the presence of largeamounts of gas enriched with heavy elements located very far from the normal stellar extent of the parentgalaxy. If such gas is present at early epochs, it could be associated with the galaxy formation processitself.

This idea has received new impetus with the detection of a cloud of ionized gas in 3C 294 that may berevealing the late stages of galaxy formation. Using the KPNO 4-m telescope, P. J. McCarthy (CarnegieObservatories), H. Spinrad, W. van Bruegel, and M. Dickinson (U. of California, Berkeley), J. Liebert(Steward Obs.), S. Djorgovski, (California Inst, of Tech.), and P. Eisenhardt (NASA Ames) have obtainedimages of a giant region of Lyman-a emission 100 x 170 kiloparsecs in extent. Once again, the long axisof the cloud is aligned with the radio source. The cloud is co-located with emission line regions in N, C,and He, and it possesses a smooth velocity gradient of 1500 km/s together with very large line widths ofup to 2600 km/s. The size of this object is very large, and the mass of the gas is estimated to be about109 solar masses. The kinetic energy of the ionized cloud alone lies in the range of 1057 to 1059 ergs, whichis an enormous amount of energy for an object perceived to be "passive." The origin of such a cloud isclearly a question of interest, especially since it has no known low redshift counterpart. One temptingpossibility is that the cloud is a remnant of the protogalactic nebula and is currently falling into the younggalaxy that formed from it. The presence of emission lines indicates an episode of early star formation,but this constraint on galaxy formation models has been known for some time. Further study of thisextreme example of high redshift Lyman-a emission is required as well as incorporation of the constraintsthese observations provide into models of galaxy evolution.

C. National Solar Observatory (NSO)

1. Near Infrared Magnetograph

The NSO Near Infrared Magnetograph (NIM) is initiating a new field of study: the spatial organizationof small-scale solar magnetic fields. It has been known for years that the photospheric magnetic fieldoutside of sunspots characteristically occurs in the form of intense (B approximately greater than 103gauss) but very compact (d < 103 km) magnetic concentrations known as flux tubes. Visible-lightobservations of flux tubes provide indirect diagnostics that must be cautiously interpreted with the aid ofmodels. Observationally, the essential difficulty is that the Zeeman splittingof spectral lines in the visibleregion is too weak to measure kilogauss magnetic fields directly.

Working at 1.56 um, NIM exploits the ^-dependence of Zeeman splitting to measure IBI, the magnitudeof the magnetic field vector (regardless of its orientation). NIM has produced the first true-field magneticmaps of solar plages. The observed field strength varies over at least the range 800-1700 gauss, comparedto an uncertainty in the individual measurements of ± 7% (forB > 800 gauss). The true field strength isonly loosely correlated with magnetic flux as measured by conventional solar magnetographs. The arealfilling factor is often greater than 0.1 and extends up to 0.5. This is larger than typical indirect estimatesbased on visible-light data and may indicate that the spectrum of flux tube sizes is weighted toward highervalues than are usually assumed in theoretical models. The individual Zeeman components are measurablybroadened, reflecting a range of field strength within individual flux tubes or among tubes within thespatial resolution element.

NIM is available to visiting observers and constitutes a unique tool for the study of solar magnetic fields.

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Figure I: Magnetic field strength in a solar plage region: as it appears to a conventional magnetograph(left) and as it is measured by the Near InfraredMagnetograph (right). The NIM measures /B(, the localmagnitude of the magnetic field vector, regardless of its orientation. The conventional magnetograph issensitive only to the line-of-sight component oflB\ averaged over the angular resolution element. Becausesolar magneticfields are concentrated into intense "flux tubes" a fraction of an arcsecond in diameter,thespatially averaged measurementprovides no information about the truefield strengths. Thenew resultsfrom NIM prove that these strong fields can be directly measured and show a significant spread in \B\with a coherent spatial pattern. The study of these "true-field" magnetograms and their relationship toflow fields should advance our understanding of magnetic fields in thephotosphere.

2. High-Precision Polarimetry

High angular resolution studies of solar vector magnetic fields are extremely important in understandingmagnetoconvective processes on the Sun, especially flare phenomena. The polarizing effect of large solar

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telescopes has proven difficult to characterize with high accuracy, thus precluding high-precisionpolarimetry, at least at visible wavelengths. Laurence November (NSO/SP) has performed an analysis ofthe polarizing characteristics of the Vacuum Tower Telescope at Sacramento Peak, and confirmed theresults by direct polarization measurements at the 1% accuracy level.

More precise polarimetry requires improved methods of calibration. To achieve this, November has carriedout a generalized formulation for ellipsometry measurements, introducing two theorems: the congruencytransform inverse and the similarity transform inverse, applicable to different calibration schemes for ageneral optical system. One of these involves simply the arbitrary rotation of a crystal sphere, a systemconfirmed in practice. Beyond this, a polarimeter design based on liquid-crystal modulators is beingdeveloped. This new polarimeter should permitunprecedented accuracy for a solar polarimeter with highangular resolution, 0.01%, so that observations will be limited only by the birefringent nonuniformity ofthe VTT window.

3. Magnetic Fields of Active Regions

Robert Howard has continued his studies of the magnetic fields of plages and sunspots. This work isaimed toward a better understanding of the surface structure and dynamics of active region magnetic fieldsand the connection of these fields to subsurface magnetic flux tubes. The overall goal is to provideadditional constraints to models of the solar activity dynamo mechanism. In recent work, it has beendemonstrated that there is good evidence in the case of plage fields, and to a lesser extent sunspot fields,for the resubmergence of at least some of the magnetic flux in the later stages of the evolution of a region.This result comes from analyses, both in the growing and decaying phases of regions, of the relativerotation rates of the leading and following portions of the regions and of the east-west inclinations of themagnetic field lines of the leading and following fields. From the same data, it is clear that the magneticfield in the growing stage of a region is in the form of a rising loop. Another study showed that growingplages are strongly inclined to lead the rotation, and growing sunspot groups are slightly inclined to trailthe rotation. This remarkable difference in the characteristics of growing surface magnetic field structureshas, to date, no explanation.

4. Progress in Adaptive Optics at NSO/SP

The Lockheed 19-segment adaptive mirror, operating on its test bed on the Sacramento Peak VacuumTower Telescope (VTT/SP), is proving to be worth the decade of development devoted to it byR. Smithson, R. Sharbaugh, S. Acton, and many others at Lockheed (LPARL). The recent modificationto the system and software, by Acton (LPARL), has allowed automatic control, via a Microvax computer,of the offsets and gains of the 38-XY channels that steer the segments. Acton also implemented electricaladjustment of the offsets of all 57 servos that tilt and phase the segments. R. Dunn and L. Wilkins(NSO/SP) improved the optical system, aligned the quad cells in the Hartmann wavefront sensor to reducethe offsets supplied by the Microvax, and calibrated the input and output of the phase network that pistonsthe segments in and out to fit them to the continuous surface of the wavefront. The calibration is soaccurate that the adaptive mirror itself can perform the correction of the overall tilt, a task that is usuallyleft to the tilt/tip mirror inserted in the beam prior to the Adaptive Mirror. Videos taken by Dunn and theVTT observers on 18 July 1991, with a sunspot as a target, show spectacular real-time improvement ofthe images (Figure 2). In the middle of the day, when the disturbing layer is close to the pupil of thetelescope and the "isoplanatic patch" is large, areas greater than 20 arcsec are considerably improved.

Real-time video solar observations with asegmented mirror are especially interesting to the adaptive optics(AO) community relative to single comparisons of corrected to uncorrected images of point sources. Thevideo images show how the system performs dynamically and, perhaps more importantly, what ishappening over the wide field of view visible in the pattern of granulation.

A 15-minute-long demonstration video has been assembled of sections of the July run. It includes asequence that demonstrates the effectiveness of the phasing network. Agroup atLockheed, led by A. Title,has enhanced the scientific value ofthis video by selecting the sharpest frames throughout the run, usingcorrelation tracking to keep the frames in precise registration, "destretching" the entire scene, and applyingsome filtering. This data processing technique, developed by Lockheed as part of the SOUP and OSLeffort, greatly improves the usefulness of ground-based observations.

Although the system has not yet been integrated into the VTT focal plane instrumentation, it is anticipatedthat itwill be used in the near future for limited scientific observations in conjunction with the engineeringruns to further refine the system. Spectrograph observations will benefit considerably from adaptive opticsbecause of their long exposures, butwill probably hav . to wait until the system is integrated into the NSOadaptive optical system.

Figure 2: Comparison of images ofa sunspot ascorrected by the Lockheed 19-segment mirror (from theobserving run of 18July 1991). Images from the corrected and uncorrected image video cameras wererecorded simultaneously on a SVHS tape recorder. This "frame-grabbed" scene has not been processedby any enhancement techniques. The tic marks are spaced 1arcsec apart. The telescope effective apertureis 35 cm. (LPARL Photo)

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5. NSO/SP "Adaptive Mirror"

Figure 3: The Sac Peak Adaptive Mirror utilizes 61 piezoelectric actuators to distort a 267-mm diameter,2.5-mm thick glassfaceplate tofit the wavefront. The 6 \un extension of each of the actuators, which weremade by Queensgate Instruments, is metered by a servo with a sensor that has a capacitor mounted onthe end of a column of the low-expansion material Zerodur in the center of each actuator. The baseplateof the mirror assembly is a 100-mm thick, 344-mm diameter iron disk. Twelve spare actuators may bemounted around the outside of the central pattern so that their attachment mounting surfaces may belapped together simultaneously with the 61 actuators in the center. A gimbal. whichfacilitates the lappingprocess, surrounds the baseplate. The glass mirror faceplate, which has steel buttons glued to it, ismagnetically attracted to the actuators. The sequence of the assembly of these attachments is demonstratedon the lower row of actuators. A central, hardened pin passes through the magnet to bear on the steelbutton glued to thefaceplate.

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6. High Velocity Wind from a T Tauri Star

The compilation of Ha profile variability data acquired during the past four years for the T Tauri star SUAurigae was completed during this year. The spectrawere obtained by the resident nighttime observer atthe McMath, Paul Avellar, as part of Mark Giampapa's synoptic program on pre-main sequence stars. Ina parallel effort, similar data were acquired at Lick Observatory in a program conducted by Gibor Basri(U. of California, Berkeley). The Tucson and Berkeley groups have since combined data sets to producean unprecedented catalog documenting the striking line-profile variability that can occur in a T Tauri staron a night-to-night basis. In collaboration with an undergraduate astronomy major at the University ofArizona, Eric DeFonso (who is now a first yeargraduate student in astronomy at the University of Texas,Austin), a movie was produced illustrating the variability seen in Ha. DeFonso also performed numerousmeasurements of line profile parameters for subsequent analysis.

A periodogram analysis of the data has led to a significant discovery, namely, the apparent modulationof the mass outflow from the star by rotation. In particular, the relative intensities of features in the bluewing of the Ha line spanning a range of velocities near ~ 150 km s"1 exhibit a modulation ofapproximately three days, which corresponds to the estimated rotation period of SU Aurigae. Thisimportant finding indicates that the relatively massive, high-velocity winds from SU Aurigae in particular,and perhaps T Tauri stars in general, can arise from localized regions on or near the stellar surface. Suchlocalized regions of 'activity' are usually associated with complexes of magnetic fields in the Sun and thelate-type stars. Hence, this interesting result implies that magnetic fields play an integral role in thestructure and, perhaps, the origin of winds in pre-main sequence stars. This hypothesis is consistent withthe Alfvdn wave models of wind acceleration that have been proposed in the past for T Tauri stars. Furtheranalysis of the data set is continuing along with the construction of preliminary models for the Ha lineformation regions.

7. Magnetic Field Measurements

The Air Force-sponsored SolarActivity Modelling Initiative requires accurate knowledge of the magneticand velocity fields observed at high spatial resolution. In order to convert the observed circularpolarization in the Zeeman-affected spectral lines to longitudinal magnetic fields, various calibrationmethods have been tested and applied to the high spatial and spectral resolution observations obtained atthe Vacuum Tower Telescope in conjunction with the NSO 20 mA filter. Observations were obtained onthe active region AR 6615 located near the disc center on 4 May 1991. The seeing was estimated to beabout 0.5 arcsec, or better, during the course of observations. The measurements consisted of sets ofmonochromatic images, in right and left circular polarization, acquired in the Fe I 5250.2 A line (Landdg = 3) at thirteen equispaced spectral points, each separated by 20 mA, and completed in fifty seconds.

The various methods applied to calibrate the line-of-sight magnetic fields from the observed circularpolarization are as follows: (a) the differences in the center-of-gravity of the right and left circularcomponents for different spectral sampling; (b) conversion of circular polarization, at particularwavelengths, to magnetic fields using model-dependent numerical solutions to the equations of polarizedradiative transfer, (c) the derivative method using the weak-field approximation. Further, retaining the highspatial resolution, the spectral resolution has also been degraded with a 120 mA bandpass filter to mimicthe observations with a typical imaging magnetograph. The Air Force grouphas made comparisons of thevarious methods mentioned above. In addition, the spectral lines have alsobeensimulated using numericalsolutions to the equations of polarized radiative transfer for a grid of model atmospheres, magnetic fieldstrengths, and their inclinations and azimuths.

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The main result of this comparison is that the center-of-gravity method yields the best calibration of theline-of-sight magnetic field, with a maximum error of about 15% for highly inclined fields. It is concludedthat a spectral sampling of 40 mA (or twice the FWHM of the Fabry-Perot interferometer) is quitesufficient to calibrate the magnetic field with reasonable accuracy.

IV. MAJOR PROJECTS

A. Global Oscillation Network Group (GONG)

The Global Oscillation Network Group (GONG) is an international project to conduct a detailed study ofthe internal structure and dynamics of the closest star by measuring resonating waves that penetratethroughout the solar interior~a technique known as helioseismology. To overcome the limitations ofcurrent observations imposed by the day-night cycle at a single observatory, GONG is developing a six-stationnetworkof extremely sensitive and stable solar velocitymappers located around the Earth to obtainnearly continuous observations of the "five-minute" pressure oscillations. To accomplish its objectives,GONG is also establishing a distributed data reduction and analysis system to facilitate the coordinatedanalysis of these data. The primary analysis will be carried out by a dozen or so scientific teams, eachfocusing on a few specific categories of problems. Membership in these teams is open to all qualifiedresearchers.

The GONG project passed a major milestone in FY 1991 when it announced the results of its site survey.The site survey activity began in 1985 and eventually included fifteen sites around the world. The finalsix sites destined to become the GONG network were announced last April at our annual meeting. Theyare Big Bear Solar Observatory, Mauna Loa Solar Observatory, Learmonth Solar Observatory, UdaipurSolar Observatory, Observatorio del Tiede, and CerroTololo Inter-American Observatory. The collectionof site survey data was then terminated at all but the six selected sites and at Urumqi AstronomicalStation, which still remains under consideration as a possible seventh site. Detailed Memoranda ofUnderstanding are currently being negotiated between the project and the various host sites.

Work on the prototype Doppler analyzer continued throughout FY 1991. After several months ofengineering upgrades, all of the primary elements of the Doppler analyzer system have been reinstalledat the prototype site and testing has resumed. This manifestation of the prototype instrument has severalsignificant improvements over the system we were working with a year ago. In addition to a newinterferometer and Lyot filter, a camera rotator is now in place, and a unique "tri-quad" solar trackingsystem has been installed and checked out. All of the electronics chassis and many of the cards in thesystem have been replaced by the production versions of the various command, control, and monitoringelectronics.

The process of choosing and acquiring the final hardware for the GONG data reduction activity was begunin FY 1991, including an analysis of the requirements for the hardware. The first step involved a studyof the time currently required to reduce the data, in addition to making estimates of the operation countsin both existing and planned software. Two hardware options are being considered: a highly centralizedarchitecture based on minisupercomputers (e.g., Convex C-3), or alternatively, a highly distributedarchitecture based on workstations or equivalent servers (e.g., HP 750). Meetings were held with variousmanufacturers to configure and price out representative system architectures. A first cut at a design showsthe centralized system to be about tenpercent more expensive. This does not include increased installationand operations costs for the centralized system for air conditioning, electric power, and maintenance. It

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also assumes extensive use of "previously owned" centralized hardware. The distributed network appearsto offer about a factor of two improvement in total bandwidth. After a more extensive review, GONGplans to select an architecture and begin hardware procurement at the end of FY 1992.

GONG continues to hold its annual meeting. Significant adjustments have been made to allow the formatto evolve as the project moves into a new phase. Starting with the April 1991 meeting, the format becameless of a review of project developmental plans for the instrument and reduction software, and moreemphasis was placed on the scientific aspects of the project. The 1991 meeting was attended by a record96 individuals from 14 countries and 37 institutions. The meeting included both oral and poster paperscoordinated by an organizing committee in response to submitted abstracts.

Over the first six years the project will have received about half of the funding proposed in the originalproject plan for that period. Since major capital outlays from the budgets of two consecutive fully fundedyears were proposed to build the stations, these progressive cuts have delayed the beginning of theobservations by at least four to five years. The project has revised its long range plan to attempt to dealwith the shortfall in capital funding. This has forced a departure from the originally proposed approachthat called for subcontracting the actual production of major systems for the instrument Much of this workwill have to occur in-house. To further facilitate this approach, GONG has made a significant contributiontoward the purchase of a numerically controlled milling machine for the NOAO shops. This instrumentwill permit cost-effective construction of production quantities of various precision-machined parts thatotherwise were to have been obtained through one or two major contracts. Further, it allows the work (andcapital outlay) to be spread out over the three years remaining in the construction phase of the project.Observations are slated to begin in FY 1994.

B. 3.5-Meter Mirror Project

This year we completed polishing the 3.5-m mirror as a sphere. The accuracy of the spherical surface is0.52 X(330 nm) peak-to-valley and0.066 X(42 nm) RMS (X = 6328 A). The Strehl ratio calculated fromthe point spread function is 0.55, and the image spot size is 0.033 arcsec FWHM.

Our optical testing capabilities continued to improve. The contrast of the interferograms was improved bya vertical test shroud that reduces air turbulence and by improvement in the mirror figure. Severalimprovements were made in the optical test software, including development of a program that calculatesa structure function from the phase map and extension of the set of Zemike terms available from 36 to80.

After completion of polishing, the thermal sensors were removed, the mirror was thoroughly cleaned, and66 Invar pads were bonded to the back surface as attachment points for the axial supports. Fabrication ofthe mirror shipping container was completed by Autry Steel, and the mirror was successfully moved toKitt Peak for coating. During the first week of December 1990 the mirror was aluminized in the 4-mcoating chamber. The resulting coating is quite satisfactory.

The main weldment of the mirror cell arrived in October 1990. It was fabricated by L&F Industries and,despite its size (14 feet across) and weight (7700 pounds), it is a precisely machined structure. Heavy steellegs have been fabricated to support the mirror cell on the 4-m polishing machine table for testing.

The aluminized 3.5-m mirror was brought down from Kitt Peak in March 1991. Arrangements were madeto have a portable crane on hand to lift the shipping container into the building and remove the lid. This

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plan worked well and helped keep the mirror out of the sun, avoiding the potential danger fromconcentrated sunlight

In FY 1991, much effort has gone into preparing the components of the mirror cell assembly, whichinclude the following: thermal sensors, blowers, air plenums, heat exchangers, and piping for the thermalcontrol system; support mechanisms, hydraulic tubing, cabling, junction boxes, position sensors, and fluidlevel control units for the mirror support system; earthquake pads, position-defining linkages, andremovable access panels.

A water chiller was designed that uses thermal electric coolers to control the temperature of the watersupplied to the mirror cell. The design of the heat exchanger plates for this chiller was optimizedempirically, and the plates were fabricated by an outside vendor.

The active optic control system was designed, fabricated, and installed. Thermal cycling tests of aprototype active support were conducted successfully. Assembly of the mirror cell, supports, coolingsystem, and control system took longer than had been forecast. By the end of June 1991 the mirror wasmounted in its cell. The cell was installed on the polishing table and ready to start the Phase II testprogram. These tests will evaluate the performance of the mirror support, thermal control, and active opticssystems.

Division SupportA Photometries Star I CCD camera and a Mac 2 computer were purchased for curvature sensingexperiments that work with the CCD to record images inside and outside of focus simultaneously. Theseexperiments were aimed primarily at developing a test system that will be useful in the optics shop andcould laterbe employed in the WIYN telescope to monitor telescope focus and image quality. This systemwas used to perform several tests during November 1991 on the SAO 1.5-m and 1.2-m telescopes onMount Hopkins to (1) evaluate the aberrations of the telescopes, (2) determine whether they come fromthe primary or secondary mirrors, and (3) locate the position of Cassegrain focus having minimumspherical aberration. Personnel from Vandenberg Air Force Base and the China Lake Naval WeaponsCenter traveled to Arizona to witness these tests. They are trying to solve problems on their owntelescopes, and the curvature sensing approach under development by NOAO may be the most promisingtest technique available. By the end of June 1991 similar tests had been conducted at the Kitt Peak 0.9-m,1.3-m, 2.1-m, and 4-m telescopes. The results of these tests will be used to determine future telescopeimprovements.

C. WIYN Project

The University of Wisconsin, Indiana University, and Yale University joined together with NOAO to formthe WIYN Consortium, Inc., incorporated in the State of Arizona in November 1990, following formalapproval of the WIYN Agreement. The WIYN Project will make use of the 3.5-m mirror described in theproceeding section. The WIYN universities are prepared to contribute a total of $8.5 M over the timeperiod 1991-1994 for the construction of a new telescope on Kitt Peak. If Wisconsin, Indiana, Yale, andNOAO meet theobligations detailed in the WIYN agreement, then the observing time remaining after theallocation of maintenance and discretionary time would be apportioned in the following way: Wisconsin26%, Indiana 17%, Yale 17%, and NOAO 40%.

During FY 1991, the project staffprepared detailed scientific and technical specifications for the WIYNtelescope. The telescope will be, to a large degree, a copy of the ARC telescope on Sacramento Peak, but

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with some modifications necessary to meet the requirements for a wide field and faster focal ratioappropriate for multi-object spectroscopy.

A contract was awarded to M3 Engineering in Tucson for architectural and engineering services to designthe WIYN Telescope enclosure and control building. A preliminary design review was held in the springof 1991, and a critical design review was planned for early FY 1992. Contractors were invited to pre-qualify to bid on construction of the enclosure and control building and four contractors were selected tobid. Site construction is expected to start in mid-FY 1992.

A design contract for the WIYN telescope mount was awarded to L&F Industries in California, the samecompany which built the ARC telescope. A preliminary design review was held in the summer of 1991,and the fabrication contract was awarded to L&F in August 1991. Detail design is underway and firstmetal is expected to be cut in the second quarter, FY 1992.

Preliminary design work was undertaken by the University of Wisconsin Controls Group, with detaileddesign of the controls system expected to begin in early FY 1992.

A 1.2-m diameter light-weighted blank for the secondary mirror has been ordered from Schott GlassTechnology. Delivery is expected in March 1992. Vendors have been asked to submit bids to polish theblank to WIYN project specifications. Work continues on the other telescope subsystems, including thetertiary mirror and the instrument adapter.

V. GEMINI PROJECT

The 8-m telescope project was officially named Gemini in January 1991, by the international steeringcommittee. The name stems from the plan to build two telescopes, one for the northern hemisphere andone for the southern hemisphere.

The NSF allocated funding for the project in FY 1991 in the amount of $4M. The funding was for initialstaffing and design work on the project and for purchasing material for the primary mirror blank.

The United Kingdom Science and Engineering Research Council announced in December 1990, itsdecision to join the project. This was a key development in advancing the partnership. A draftMemorandum of Understanding was prepared during the year outlining the terms of the agreement andthe plans for establishing the partnership, which would involve Canada, the U.K., and the U.S. In addition,Canada continued its planning efforts for astronomy and considered how the project would be integratedinto the overall Canadian astronomy program.

intemati il search for the Project Manager mated in January 1991 with the selection ofLawrence K. Randall, Jr. Randall's previous expe; e inc Jes the positions of Engineering Managerfor the KPNO and CTIO 4-m telescopes and Program Manager for the Faint Object Spectrograph for theHubble Space Telescope. Randall began work in March 1991. At the close of FY 1991, he had selectedthree Engineering Managers: Henry Blair, for the Building and Enclosure Group. Keith Raybould, for theTelescope Mounting Group; and Larry Stepp, for the Optics Group. Patrick Osmer was named Ir rimProject Scientist by the international steering committee for the project.

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The international partners agreed that the project should be located atNOAO Tucson headquarters duringthe design and construction phase. NOAO provided space for the initial work on the project by purchasingand installing modular buildings on the east roof of its main building.

Ameeting was held in September 1990, at the Dominion Astrophysical Observatory in Victoria, B.C., todiscuss the scientific goals of the project, compare theengineering and costing efforts made to date in thedifferent countries, and assess how work packages for the project might be distributed among the differentcountries. One outcome was the recommendation that a Science Advisory Committee be formed to developthe Science Requirements for the project. Such a group was formed on a provisional basis and met, inNovember in Oxford, to identify the mainscience goals of the project and begin the process of developingthe science requirements. The U.S. was represented by F. Gillett, R. Green, R. Schommer, and P. Osmer.In addition to the scientific goals described in the national proposals, the meeting identified highperformance at infrared wavelengths, particularly outstanding image quality and low emissivity, as majorgoals for the project

The report of the Astronomy and Astrophysics Survey Committee was released in March 1991 andincluded recommendations for an IR-optimized 8-m telescope for Mauna Kea and a southern 8-m opticaltelescope. AURA directed NOAO to study the implications of the report and its relation to plans for theGemini telescopes. As a result, F. Gillett led an effort to define what IR-optimization would mean intechnical and design terms for the telescopes. This effort was integrated with the overall U.S. and Geminiprocess to define the performance requirements for the telescopes. The process was underway by the endof FY 1991 with plans to produce a draft of the Gemini science requirements for the October 1991meeting of the Interim Gemini Board.

VI. INSTRUMENTATION

A. CTIO

During FY 1991, the CTIO staffcontinued its efforts to carry out a detailed site study for the location ofthe southern 8-m telescope of the Gemini project, and for the 4-m telescopes planned by universityconsortia. This study hasconcentrated on Cerro Pach6n, the tallest mountain on theTololo property. CerroPach6n was chosen as the primary site because its elevation (2,725 meters) is higher than Tololo, andbecause previous site surveys showed that it is possibly a superior site. The north face is a vertical cliffthat faces into the prevailing north wind.

In order to make a direct comparison with the results of the NOAO site surveys of Mount Graham andMauna Kea, the same site testing equipment used in these surveys was installed on Cerro Pach6n. Thisequipment includes a 12-inch telescope used as a seeing monitor, echosondes to measure the lower levelatmospheric turbulence, 30-m towers equipped with anemometers, thermometers, and microthermal arrays,and IRsky radiance monitors todetermine sky emissivity and water vapor content. An analysis of the dataobtained since this study was initiated in July 1988 confirms the findings of the previous site surveys thatPach6n is an excellent site. However, in order to more fully compare the Cerro Pach6n site with othersouthern sites, the fabrication of two copies of the seeing monitors used for the Las Campanas ObservatoryMagellan project site survey was undertaken in FY 1991. These telescopes, which are capable ofmeasuring the one dimensional image motion from 2 to 200 Hz, have been tested simultaneously with themonitor used for the European Southern Observatory (ESO) Very Large Telescope site survey and havebeen found to give identical results. The results from these new seeing monitors can bedirectly compared

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to the Las Campanas and ESO surveys. The first of the seeing telescopes was installed on Cerro Pach6nat the end of FY 1991, and plans call for the second to be installed on Tololo early in FY 1992.

1. Array Controllers

In late FY 1989, CTIO initiated a project to replace its aging array controllers. While these controllershave given excellent service over more than a decade, they are now showing their age, both in decreasingreliability and in lack of flexibility (e.g. the ability to read out multiple amplifiers on large-formatdetectors). A standard system architecture was defined joindy with KPNO. KPNO also participated insubsequent design and fabrication efforts. During FY 1991, the first prototype controller was completedand tested at the telescope. A modified prototype is to be tested in October 1991, with limited replicationoccuring shortly thereafter. A full production version will be produced later in FY 1992. The currentversion runs on the Tololo Sun computers, of which there are now one per telescope, including theSchmidt. A simple user interface permits the user to take CCD images and process them under IRAF; amore sophisticated interface will eventually be implemented, jointly with KPNO, as an NOAO standard.

2. 4-m Prime Focus Corrector and Atmospheric Dispersion Correction; Large FormatPrime Focus CCD

A prerequisite for wide-field imaging at CTIO is the replacement of the older triplet correctors at theprime focus with a more modern design, which would produce better image quality over a wide field andwould also provide better achromatic performance and good dispersion correction over the field. Thisproject has been delayed substantially by difficulties encountered by the vendor in the fabrication andtesting of the individual optical elements. However, almost all the elements are now completed and tested;mechanical and electrical design and construction of the mount are also largely complete, awaiting onlydelivery of the complete set of optical elements. The new corrector should be commissioned on the 4-mtelescope for use for prime-focus photography and with Argus, the multi-fiber-feed spectrograph, in early1992.

The new prime focus CCD unit is intended to permit use of large-format CCDs (up to 2 x 2 mosaics of2048 x 2048 detectors with 15 um pixels) with the new corrector. Work on this project will be completedsoon after the new corrector is commissioned.

3. CCD TV Acquisition Cameras

This project begun in FY 1988, was intended to produce sensitive TV acquisition cameras. A successfulprototype was completed in 1989, and production work began later that same year. During the course oftesting, it became clear that the camera could also be used for precise guiding. A number of modificationswere made to enhance this capability and increase dynamic range.

Production has been carried out using a Chilean sub-contractor (DTS, ex-ENAER) to handle electronicfabrication and much of the board and assembly-level testing. This type of sub-contract work is likely tobe used increasingly in the future for well-defined project tasks. Five of the nine cameras to be producedfor CTIO have been completed and are in use on Tololo; the construction of the remaining four camerasfor CTIO will take place at the end of 1991.

In addition to production of cameras for CTIO, copies of the cameras are being built, or will be built, forESO, Las Campanas, and KPNO.

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4. 4-m Telescope Seeing Improvements

In FY 1991, CTIO began a long-term program of improving image quality at the 4-m telescope. Theseefforts will extend over several years as CTIO attempts to achieve image quality at the telescope that isas close as possible to the intrinsic superb image quality of the site.

The first year of effort has concentrated on two areas: elimination of major heat sources in the 4-m domeand detailed analysis of the 4-m telescope optics. In the first area, activities that are not direcdy relatedto the operation of the telescope (e.g., library, electronics shop) have been moved outof the dome to otherlocations on the mountain; while resulting in some inconvenience to observers and mountain personnel,this move has substantially reduced heat generated within the dome. A project to cool the oil deliveredto the horseshoe is nearing completion, and work to move the console room below the chilled floor levelhas also started; the present console room will be used only for set-ups, with a minimum of equipmentturned on. Work is also beginning on design of a vent system to provide better airflow through the domearea by means of a system of large vents or doors in the dome. Water tunnel studies indicate that thesevents will provide good passive airflow without the need for fans, which are expensive to operate.

Studies of the telescope optics have been carried out with the assistance of people from both ESO andKPNO. The purpose of these studies is fourfold: to optimize optical alignments, to identify deficiencies(if any) in the optical system that can be remedied by further project work, to identify areas whereadditional, active control would produce improvement, and to develop sufficient in-house expertise tomaintain the resulting system at peak performance.

5. Other Projects

A number of improvements were made to the Rutgers Fabry Perot mostiy improved comparison lampinterface and a mechanical interface to the CTIO filter bolts. A variety of interference filters werepurchased for use with this instrument and for direct imaging

The design of the second generation imager has been simplified in order to reduce the resources requiredfor completion and to permit itsuse on a greater number of the CTIO telescopes. As now designed, it willbe usable on all CTIO imaging telescopes, including the Schmidt An order has been placed for a256 x 256 HgCdTe array (NICMOS III) from Rockwell, which will provide high-QE imaging in the1-2.5 (im region, both broadband and narrowband. Mechanical design work will begin once the opticaldesign is completed and theoptics are ordered; the instrument electronics will be based on the new arraycontrollers described above.

B. KPNO

In the period July 1990 through June 1991, significant progress was made at KPNO in the areas ofinstrumentation and in critical areas of operations on Kitt Peak. These activities are consistent with, andmotivated by, the long range view of the role of KPNO in meeting the present and future needs of theU.S. astronomical community. Kitt Peak is a very good site, in terms of both seeing and sky brightness,and it is anticipated that its viability will persist well into the next century. In light of this, and in viewof the coming presence of new telescopes and instrumentation on the mountain, a significant change inmountain management was begun with the hiring of a new manager for all operations on the site. BruceBohannan arrived in January 1991, to fill this new position, marking the beginning of many improvementsin the operation of Kitt Peak, all of which are ultimately motivated by the goal of providing the most

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effective possible acquisition of astronomical data. Changes involve improvements in procedures, inorganization, and in the implementation of new programs such as seeing improvements and telescopeupgrades. In addition, better processes for identifying critical maintenance areas are being developed, andsome long standing and much needed maintenance items are finally being addressed.

In the area of instrumentation, activities are proceeding in an integrated manner that reflects a clear viewof the role of KPNO in the future of astronomical research and in NOAO projects in particular. Thedevelopment of the fiber-fed multi-object spectrometer will not only provide state of the art observingfacilities at the KPNO 4-m telescope, but will also be integrated into the new 3.5-m WIYN telescope whenit arrives on Kitt Peak. In addition to testing the 3.5-m mirror for this telescope and in assisting in theplanning stages for the project, KPNO has begun to solicit community advice on the operational aspectsof this facility. Detector development is also being carried out with future projects in mind, both in theevaluation of large format, high quantum efficiency infrared array detectors and in the development ofCCD foundry runs and thinning technology. These activities will have a direct influence oninstrumentation projects being developed for the NOAO proposed 8-m telescopes.

Instrumentation

Major accomplishments in FY 1991 in the optical and ultra-violet (O/UV) instrumentation program includethe completion of the bench spectrograph and commissioning of the multi-fiber positioner to feed thisinstrument. In addition, continuing progress was made in the areas of CCD mosaic design and in CCDcontrollers and CCD development. In the area of IR instruments, major accomplishments were thecompletion and commissioning of the four-color IR camera (SQIID), the completion of the fast electronicseffort, and the achievement of major advances on the cryogenic optical bench project. Each of these isbriefly described below.

1. Fiber-Fed Bench Spectrograph

This instrument is now placed in a stabilized room specifically designed for this purpose. First light hasbeen obtained with a red-optimized camera. Construction of a blue camera is underway. Construction ofa cell to hold R-C gratings and automation of some critical components for increases in operationalefficiency have been completed. A great deal of work was devoted to developing software to control thefiber positioners in an optimum and safe manner. Modifications to the x-y stage of the multi-fiber feedwere made to overcome flexure problems present in the early design. Multi-object spectroscopy providessuch enormous gains in throughput that it is anticipated that this instrument will be one of the mostoversubscribed in the KPNO inventory.

2. CCD Mosaic Imager

The imager will be a mosaic of four 2048 x 2048 (or equivalent) CCDs in a common dewar. This projectincludes shutter and filter wheel interface to the 4-m prime focus, CCD controllers, and data handlingcomputer hardware. Work in FY 1991 included preliminary design study, corrector design, conceptualdesign of the dewar, and design of readout electronics and power supplies. The project could be completedin two years. This long-term proposal represents the major new start for the group. CTIO is collaboratingin this reject, and the goal is to deploy a second imager in Chile.

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3. Four Color Camera (SQUID)

This instrument has now been commissioned. Four 256 x 256 PtSi array detectors view simultaneouslythe same area of sky at wavelengths J, H, K, and L (1.2, 1.6, 2.2, and 3.5 urn). This large-field-of-viewcamera is used primarily in a "telescope raster" mode to build up images of a square degree or more insize. On-line data reduction is emphasized. The capability for simultaneous J, H, K imaging polarimetryhas been designed already into SQUID; this function is enabled by the addition of a warm super-achromatic half-wave plate and a cooled analyzer. Closed cycle coolers are in use at the 1.3-m and removethe need for liquid cryogens in this and all subsequent instruments.

4. Cryogenic Optical Bench

The bench provides a versatile combination of broadband and narrowband filters, a polarimeter, animaging Fabry-Perot a coronagraph, and grisms in a single cryostat. The emphasis is on modular design;for example, the instrument will be commissioned with a low quantum efficiency PtSi detector. When asatisfactory large format high QE detector becomes available, the upgrade will necessitate no more thana straightforward plug-in module replacement. Much of the design work for the bench was done in 1991.

5. Infrared Developments for 8-m Telescopes

The KPNO Infrared Program is positioning itself to meet the requirements of the NOAO 8-m telescopes.Infrared astronomers are becoming increasingly aware of the potential of adaptive optics for imageimprovement. The 2 urn window is a particularly good place to work because the background from bothatmospheric airglow and thermal emission is relatively low. The KPNO Infrared Program will enter thisfield with a development program that begins with relatively simplemodifications to existing facilities andinstruments. The first step will be adaptive correction to image motion through simple tilt correction,which should reduce the 2-3 u.m image diameter by a factor of 2 in Kitt Peak median seeing. Work isproceeding at the 2.1-m telescope under contract with the Gemini project A CCD camera will be usedto provide a continuous position readout for the reference star, which may be any star in the field. Therequired brightness of the reference source will depend on atmospheric conditions, but will be sufficientlyfaint that the image stabilization option will be of wide applicability. The error signal will be used to closea fast guiding loop with the existing 2.1-m two-axis IR secondary.

This "fast guiding" endeavor is directly applicable to the design of an infrared optimized telescope. Thenecessary tests on optimized mirror coatings are now being initiated, and, by virtue of the cryogenicoptical bench approach to instrument construction, the present generation of KPNO instruments can beregarded as prototypes for the 8-m telescopes.

6. PHOENIX

The experience gained at KPNO with CRSP, a low- and medium-resolution array spectrometeremployingan SBRC 58 x 62 InSb array, amply demonstrates the power of IR arrays for spectroscopy. The opticaldesign for the high resolution (R = 100,000) long-slit spectrometer PHOENIX is now complete, and workis proceeding on the mechanical design. This instrument will continue the strong tradition of highresolution IR spectroscopy begun at KPNO with the 4-m FTS and, because of the improvements indetector technology, will provide much greater sensitivities. For this reason, it will also be effective to usePHOENIX on the 1.3-m and 2.1-m telescopes.

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C. NSO

1. Spectromagnetograph

The NASA/NSO Spectromagnetograph, developed jointiy by the Goddard Southwest Solar Station andthe National Solar Observatory, is now operating at the NSO/Kitt Peak Vacuum Telescope and is availablefor mission support and individual research by qualified scientists. This instrument will replace the two-slitdetection used by the current 512-Channel Magnetograph. The spectromagnetograph records long-slit,spectrally resolved line profiles in left- and right-circularly polarized light and analyzes the data in cadencewith spatial scanning of the solar image to produce digital maps with approximately one arcsec pixels ofline-of-sight magnetic and velocity fields, continuum intensity, equivalent width, and line depth. Duringthe past year, software to accomplish the real-time analysis was implemented. A final optical reimagingsystem was designed and fabricated, and it is being installed at the telescope. Data were obtained fornumerous campaigns, rocket flights (e.g., GSFC's SERTS 4 flight), and individual projects using prototypereimagingoptics. Upgrades for the data control computer and video processor system have been purchasedthat will improve the speed, quality, quantity, and reliability of the real-time analysis.

2. He 10830 A Video Filtergraph/Magnetograph

A new instrument for high spatial and temporal resolution imaging of solar active regions and flares inthe 10830 Aline of He I is being developed under the Memorandum of Agreement between AURA andNASA/GSFC for use at the NSO/Kitt Peak Vacuum Telescope. The instrument will be able to runsimultaneously with the spectromagnetograph. This line provides a unique view of the solar chromosphereand corona since the emission is produced in the high chromosphere but also responds to EUV coronalradiation incident from above. The instrument is based on a five-element Lyot filter to provide differentialdual bandpass response and polarization modulation. Preliminary design and purchase of key opticalelements were completed during the past year.

3. Near-Infrared Magnetograph

The Near-Infrared Magnetograph measures true magnetic field strengths in the deep solar photosphereusing the McMath telescope, the vertical spectrograph, and the Zeeman-sensitive line Fe 15649 A. Thedesign of the Near-Infrared Magnetograph consists of three main subsystems, an infrared imager run infast framing mode (currentiy the NOAO 68 x 52 InSb array detector), a liquid crystal polarizationmodulator, and a raster-scanning solar limb guiding system. Data taken with a prototypesystem in January1990 have been analyzed and submitted for publication. In FY 1991, the bread-boarded instrumentachieved its primary operational goal, a two-dimensional true-field magnetic map of the Sun. In earlyFY 1991, an Amber Electronics 128 x 128 InSb array detector system was purchased for use with NIM.Work has progressed steadily throughoutFY 1991 on the control and I/O software required to operate theAmber system. The first use of the Amber with NIM is expected in early FY 1992.

4. High-I Helioseismometer

The joint NASA/GSFC, Bartol, and NSO High-/ Helioseismometer allows observations of high-/ (shortwavelength) acoustic p and f modes to be made regularly at the NSO/Kitt Peak Vacuum telescope. Theinstrument design employs a versatile CCD image processing system coupled with a 1024 x 1024 CCDwhich records a full disk image of the Sun through a K-line interference filter. The observations will beperformed approximately three days per month after die normal synoptic program at the NSO/Kitt Peak

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Vacuum Telescope. Inearly FY 1991, the instrument was taken to the South Pole for the austral summerobserving season. Upon its return from Antarctica, the system was installed in a temporary fashion at theNSO/KP Vacuum Telescope. It is anticipated that the final mounting system will be installed in earlyFY 1992.

5. Stellar K-line Filter

Present techniques for measuring stellar rotation and activity cycles are restricted to observing one starat a time, a sequential procedure that is both slow and laborious. With the Stellar K-line Filter, many starswill be observed simultaneously in open clusters. Studies of open clusters have proven crucial in theverification and extension of the theory of stellar structure and evolution. Development of a temperaturestabilized, tunable, narrow-band Ca II K-line filter is well underway. The filter is designed to havesufficient field of view to image an area several arcmin in extent. The filter, which was released forscientific tests in FY 1991, will be mounted in front of a UV-enhanced 800 x 800 CCD, and observationswill be made at the McMath telescope. During preliminary testing a serious flaw in two of the opticalelements was discovered. Further work has been put on hold, subject to the resolution of this designproblem.

6. Solar-Stellar Cross Dispersion

The Reticon detector at the McMath stellar spectrograph was replaced in 1987 with a UV-enhanced800 x 800 CCD. Although the speed gains (2 magnitudes) with the CCD have been remarkable, thisdetector is physically smaller than the retired Reticon and permits only halfthe former spectral length tobe covered in an average exposure. Cross-dispersing the echelle grating will offset this disadvantage byplacing four to five orders in a well separated format onto the CCD. The optical design must take intoaccount the anticipated upgrade to a 1024 x 3072 Ford Aerospace CCD. This detector upgrade istentatively planned for early FY 1993.

7. McMath 4-m Upgrade Study

A 4-m, all-reflecting solar telescope would foster new science in the infrared between 1 u,m and 20 um.At 12 um, where seeing is significantly better than in the visible, a diffraction limit of 0.75 arcsec wouldensure the direct measurement of non-sunspot magnetic fields in the high photosphere. Asteroseismologywould become feasible for solar-type stars as faint as V = 7. The telescope superstructure would remainunchanged and most instruments would need only slight modification. Internal image quality would bepreserved by the use of liquid-cooled, actively-supported, aluminum-based mirrors. The first step, executedin FY 1991, was to conduct an engineering study to determine, in detail, the technical feasibility of theproposed project and to better understand the costs involved. The engineering report is due in earlyFY 1992.

8. Adaptive Optics Systems

The Lockheed Adaptive Optics (AO) System has been developed by Scott Acton of Lockheed to allowsubstantial automatic control. Further improvements by Richard Dunn and Larry Wilkins of NSO/SPgreatly improved the stability of the system to the extent that an extended observing sequence has beenachieved with it The video movie obtained during the observing run clearly demonstrates proper phasingof the AO sub-aperture mirrors. While this system is not optimized, the quality of image improvementpoints to the substantial resolution gain possible for ground-based solar observations with the use of

23

advanced adaptive optics systems. The development of the digitally-based NSO/SP AO system hascontinued. The large mirror system and actuators have been assembled and vacuum tested, while work hascontinued on achieving adequate flatness of the thin mirror surface. The digital reconstructor has beendesigned and is now under development (external contract). Other aspects of the system, such as thewavefront sensor, have undergone further development. In addition and as an ongoing program, the wholeoptical configuration of the VTT instrumentation has been modified to incorporate an AO system as astandard part of the instrumentation. This work has also involved the development of a horizontalspectrograph and other significant modifications to the overall system.

9. Correlation Tracker

This project has been completed. In a joint program with Kiepenheuer Institut fur Sonnenphysik (KIS),two Correlation Trackers have been constructed, one now in regular use at NSO/SP, the other at KIS.More advanced designs are under review for an eventual Mk II version that would have more universalapplications while being more supportable and simpler in design concepts and hardware.

10. One-Shot Coronagraph Upgrade

This program has involved incorporation of a CCD imaging and programmable observing sequencecapability, while retaining the option of the original high-resolution film recording method. The requiredopto-mechanical system has been completed, while the CCD array and associated electronics and computersystem, have been implemented to the point of imaging tests.

11. Perkin-Elmer Computer System Replacement at NSO/SP

This is part of a major program to update the hardware and software computer systems of the VacuumTower Telescope (VTT) Facility and the Evans Solar Facility (ESF). These systems will then be a modelfor the development of the Hilltop Observing Facility. For the VTT and ESF, hardware has beenpurchased and substantial work completed on data acquisition software and generic instrument modules.

12. Other Projects at NSO/SP

In addition to the above projects, other instrumentation development has been achieved, primarily throughUSAF funding. Principal projects only are mentioned here. The Mk II version of the White-Light-Flaretelescope has been completed and tested and will soon be mounted on the Hilltop Spar. The VectorMagnetograph (Applied Physics Lab., Johns Hopkins University), mounted in the Hilltop Facility, has beenimproved in its reliability througn optical, mechanical and electronic refinements, as part of a prototypingphase, to achieve accurate magnetic field observations. This work continues. The narrow-band (= 20 mAat 5000 A) Fabry-Perot filter has been incorporated in the VTT Facility. Following thorough testing andcalibrating, it is now available for general use. The major program of the development of reflectingcoronagraphs has continued with the modification of the second prototype (MAC II), which has a 15-cmaperture superpolished objective mirror. A new secondary optical system (including a special metal annularfield mirror) produced at Institut d'Astrophysique de Paris, was incorporated into MAC II, while theobjective mirror mount was modified to allow ready inspection and cleaning of the mirror. Tests arecontinuing of the overall system. An advanced optical design for MAC III (55-cm aperture) has beencompleted that is capable of producing high angular resolution over an extended field.

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VII. CENTRAL COMPUTER SERVICES

Tucson computing: A VAX 4000-200 was installed as replacement for the soon-to-be-retired VAX 8600.Time-shared Sun systems Tucana and Orion were upgraded from 3/160 and 4/280, respectively, toSparcstation 2 systems. The shared Sun 4/470, designated Ursa, will replace the 8600 as our mostpowerful computer system. In the next few months Ursa will be upgraded to a 4 processor CPU with 128Mb of memory. The number of systems in the Scientists Workstation Network was increased from 22 to30, and a number of X-window terminals were installed, thus bringing modem desktop computing to mostof the scientific staff. These changes continue our long-term plan to phase out support for VMS, providea networked combination of powerful shared and personal computer systems for the scientific andtechnical staff, and significantiy reduce our utility and maintenance costs.

A data line, Tl capacity (1.5 Mb/sec) leased from AT&T, bringing an Internet connection to Kitt Peak,was enthusiastically received by staff and visitors alike, but will have to be throttled back to lowerbandwidth owing to very large lease cost increases.

Following several years of planning, the aging and expensive Dicomed image recorder was replaced witha Solitaire8, which accommodates 35, 70 mm roll film and 3 x 4 inch sheet film and polaroid module.This recorder offers approximately double the resolution of the predecessor and will operate with far lessmanual intervention. Convenient color imaging will be among the many new capabilities available withthe Solitaire image recorder.

IRAF: Release 2.10, the first major release of IRAF in more than a year, is in beta testing at this writingfor release in 1992. Many applications software additions are included for image processing, digitalphotometry, one- and two-dimensional and multi-object spectroscopy. System improvements includeimplementation of the world coordinate system for spectroscopy and plotting. New magtape support isprovided with a table-driven interface, which accommodates all modem cassette and cartridge tape units.

A major effort during the yearwas the further development of the IRAF Control Environment (ICE), nowin use at all KPNO telescopes, which allows users to control telescope and data acquisition from an IRAFwindow. The first version of ICE was implementedby S. Schaller (Steward Observatory) and subsequendyimported to NOAO and considerably modified. As IRAF is widely used in the astronomy community,visitors find that ICE offers a familiar environment common to all telescopes and instruments as well asdata reduction. User response has been very positive.

During FY 1991 considerable attention was given to planning for the international Astronomical Softwareand Data Analysis Systems conference, scheduled for November 1991, to be jointly hosted by NOAO,STSCI and SAO. More than 300 astronomers from 20 countries are registered to attend.

In the period 1 July 1990 through 30 June 1991, a total of 218 visiting scientists used the VAX 750s,VAX 8600, and workstation computing facilities at NOAO Tucson.

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VIII. PERSONNEL

A. CTIO Scientific Staff Changes

Darren DePov, Post-doctoral Research Associate, was offered a position of Assistant Professor ofAstronomy at Ohio State University and left CTIO on 14 September 1990.

Andrew McWilliam, Post-doctoral Research Associate, left CTIO on 10 August 1990 to take up a positionof Assistant Professor of Astronomy at New Mexico State University, Las Cruces.

Mark Phillips, Astronomer/Tenure, was appointed CTIO Assistant Director on 1 October 1990.

Robert Schommer was hired at the position of Associate Astronomer and started working at CTIO on1 September 1990.

Nick Suntzeff, Associate Astronomer, was granted tenure on 25 January 1991.

Donald Temdrup, Assistant Scientist, left CTIO on 9 August 1990 to accept an Assistant Professorshipat Ohio State University.

Robert Williams, CTIO Director/NOAO Associate Director, began an eleven month sabbatical on16 May 1991.

Gerard Williger, Post-doctoral Research Associate, started at CTIO on 20 February 1991

B. KPNO Scientific Staff Changes

Bruce Bohannnan was hired at the position of Scientist and started working at KPNO on 2 January 1991.

Beatrice Miiller (European Space Operations Center, Germany) was appointed to the position ofPost-doctoral Research Associate on 9 August 1990.

David Silva (U. of Michigan) was appointed to the position of Post-doctoral Research Associate on14 November 1990.

C. NSO Scientific Staff Changes

Craig Gullixon was hired as a Senior Associate in Research at NSO/Sacramento Peak and started on25 February 1991.

Frank Hill was reclassification from Associate Astronomer to Scientist at NSO/Tucson on 1 January 1991.

Deborah Haber, Post-doctoral Research Associate, left NSO on 24 August 1990 to take up a teachingposition in the Physics Department at Colorado College.

Greg Kopp, Post-doctoral Research Associate, started working at NSO/Tucson on 1 October 1990.

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IX. DIRECTOR'S OFFICE

The current management structure for NOAO consists of the following employees: Sidney Wolff, NOAODirector, Pat Osmer, Deputy Director for NOAO; Dave De Young, Associate Director of NOAO forKPNO; John Leibacher, NSO Director/NOAO Associate Director, Robert Williams, CTIO Director/NOAOAssociate Director. Mark Phillips, CTIO Assistant Director, Yvette Estok, Assistant to the NOAODirector, Robert Barnes, Assistant to the KPNO Director, Glen Blevins, Controller/ Manager, CentralAdministrative Services; Larry Daggert, Manager, Engineering and Technical Services; John Dunlop,Manager, Central Facilities Operations; Karie Meyers, Public Information Officer; Steve Ridgway,Manager, Central Computer Services; and Ray Smartt, Deputy Director for NSO/Sacramento Peak.

The Director and her staff are responsible for the overall operation of NOAO. The Director is responsiblefor providing scientific leadership for NOAO, determining priorities, budget planning, and allocation ofresources. The Director represents NOAO, and in particular, the three scientific divisions (CTIO, KPNO,and NSO) to AURA, Inc., the National Science Foundation, and to the scientific community.

27

APPENDIX A

National Optical Astronomy ObservatoriesJuly 1990 to June 1991 Technical Reports

Barr, L.D.. et al. 1990, SPIE, 1236, p.492, "Seeing Studies on a 1.3 M Mirror"

Barr, L.D., et al. 1990, SPIE, 1236, p.812, "Air Flow Studies in Channelled Mirrors"

Dryden, D.M., Pearson, E.T. 1990, SPIE, 1236, p.825, "Multiplexed Precision Thermal MeasurementSystem for Large Structured Mirrors"

Ellis, T., et al. 1990, SPIE, 1235, p.361, "A Unique Design for Use of Closed Cycle Refrigerators forAstronomical Observations"

Forbes, F.F., Kutyrev, A. 1990, SPIE, 1236, p.480, "Intercomparison of American andSovietStellarImageMotion Monitors"

Fowler, A.M., Joyce, R.R. 1990, SPIE, 1235, p.151, "Status of the NOAO Evaluation of the Hughes 20x64Si:As Impurity Band Conduction Array"

Ming, L. 1990, SPIE, 1236, p.334, "Removable Atmosphere Dispersion Corrector for 8-M TelescopeDesign"

Osmer, P.S. 1990, SPIE, 1236, p.18, "The NOAO 8-M Telescopes Project"

Pearson, E.T. 1990, SPIE, 1236, p.628, "Hartmann Test Data Reduction"

Roddier, C, Roddier, F. 1990, J. Opt. Soc. Am., 7, p.1824, "Diffraction-Limited Imaging of UnknownObjects Through Fixed Unknown Aberrations Using Interferometry"

Roddicr, F., Graves, J.E., Limburg, E. 1990, SPIE, 1236, p.474, "Seeing Monitor Based On WavefrontCurvature Sensing"

Roddier, F., et al. 1990, SPIE, 1236,p.485, "Seeing at Mauna Kea: A Joint UH-UN-NOAO-CFHT Study"

Roddier, N. 1990, SPIE, 1237, p.668, "Atmospheric Wavefront Simulation and Zemike Polynomials"

Roddier, N. 1990, Opt. Engineering, 29, p.1174, "Atmospheric Wavefront Simulation Using ZemikePolynomials"

Siegmund, W.A., Stepp, L., Lauroesch, J. 1990, SPIE, 1236, p.834, "Temperature Control of LargeHoneycomb Mirrors"

Siegmund, W.A. et al. 1990, SPIE, 1236, p.567, "Flow Visualization of Four 8 M Telescope EnclosureDesigns"

Stepp, L. 1990, SPIE, 1236, p.615, "3.5M Mirror Project at NOAO"

Tsay, W.-S., et al. 1990, PASP, 102, p.1339, "Anderson Mesa, Arizona, As A Site For An Optical Array"

APPENDIX B

Cerro Tololo Inter-American ObservatoryJuly 1990 to June 1991 Publications List

During the period 1 July 1990 through 30 June 1991, 217 separate observing programs involving 332scientists were carried out at CTIO. In the same time period, 268 papers were published based on the useof Cerro Tololo facilities.

Aaronson, M., et al. 1990, ApJS, 73, p.841, "Northern Milky Way Carbon Stars: New Candidates, JHKPhotometry, and Radial Velocities"

Anguita, C.A., Ruiz, M.T. 1990, IAU Symposium 141, eds. J.H. Lieske, V.K. Abalakin (Dordrecht,Kluwer), p.455, "CCD Parallaxes for Faint Southern High Proper Motion Stars"

Anthony-Twarog, B.J., et al. 1991, AJ, 101, p. 1902, "Call H and K Filter Photometry onthe uvby SystemI. The Standard System"

Anthony-Twarog, B.J., Twarog, B.A., Suntzeff, N.B. 1991, ASP Conference 13, ed. K. Janes (ASP),p.227, "CCD Strdmgren Studies in NGC 6397"

Armandroff, T.E., Da Costa, G.S. 1991, AJ, 101,p.1329, "Metallicities for Old Stellar Systems from CallTriplet Strengths in Member Giants"

Aumann, H.H., Probst, R.G. 1991, ApJ, 368, p.264, "Search for Vega-Like Nearby Stars with 12 MicronExcess"

Bailyn, CD. 1990, Accretion Powered Compact Binaries, ed. C.W. Mauche (Cambridge U. Press), p.55,"Optical Counterparts for Globular Cluster X-ray Sources"

Bailyn, CD., et al. 1991, ASP Conference 13, ed. K. Janes (ASP), p.363, "The Optical Counterpart of theX-Ray Source in NGC 6712"

Balachandran, S., Anthony-Twarog, B.J., Twarog, B.A. 1991, ASP Conference 13, ed. K. Janes (ASP),p.544, "Lithium in F Dwarfs in IC4651"

Baldwin, J.A., et al. 1990, ApJ, 374, p.580, "Physical Conditions in the Orion Nebula and an Assessmentof its Helium Abundance"

Bergbusch, P.A., VandenBerg, D.A., Infante, L. 1991, AJ, 101, p.2102, "BV CCD Photometry of the OldOpen Custer NGC 2243"

Bcrgmann, T.S., Bica, E„ Pastoriza, M.G. 1990, MNRAS, 245, p.749, "The SteUar Population andEmitting Gas in the Inner 2-5 KPC for a Sample of 9 Seyfert 2 Galaxies"

Bertola, F., et al. 1991, ApJ, 373, p.369, "Testing the Gravitational Field in Elliptical Galaxies:NGC 5077"

Binney, J.J., Davies, R.L., Diingworth, G.D. 1990, ApJ, 361, p.78, "Velocity Mapping and Models of theElliptical Galaxies NGC 720, NGC 1052, and NGC 4697"

Blanco, V.M., McCarthy, M.F. 1990, AJ, 100, p.674, "Identification of 849 Cool-Carbon LMC Stars"

Bond, H., Ciardullo, R. 1990, ASP Conference 11, eds. C Cacciari and G. Cementini (ASP), p.529,"Pulsations of Central Stars of Planetary Nebulae"

Bond, H., Meakes, M. 1990, AJ, 100, p.788, "The Pulsating Nucleus of the Planetary Nebula Longmore 4"

Bothun, G., et al. 1991, AJ 101, p.2220, "Carbon Stars at High Galactic Latitude"

Bouchet, P., et al. 1991, A&A, 245, p.490, "The Bolometric Light Curve of SN1987A. II. Results fromVisible and Infrared Spectrophotometry"

Bridges, T.J., Hanes, D.A., Harris, W.E. 1991, AJ, 101, p.469, "The Globular Custer System ofNGC 1399"

Briley, M.M., Hesser, J.E., Bell, R.A. 1991, ApJ, 373, p.482, "C and N Abundances Among 47 Tuc MainSequence Stars"

Brown, J.A., Wallerstein, G., Oke, J.B. 1990, AJ, 100, p.1561, "High Resolution CCD Spectra of Starsin Globular Clusters V: Carbon, Nitrogen, and Oxygen Abundances in Stars in 47 Tuc M4, and M22"

Buta, R. 1991, ApJ, 370, p.130, "Weakly Barred Early-Type Ringed Galaxies IV. The Double-Ringed SO+Galaxy NGC 7702"

Caldwell, N., et al. 1991, ApJ, 370, p.526, "A Study of Star Formation in Sa Galaxies"

CardeUi, J.A., et al. 1990, ApJ, 362, p.551, "Molecules Toward HD 62542: a High Density, PeculiarExtinction Sight Line in the Gum Nebula Complex"

Chaboyer, B., Vader, P. 1991, PASP, 103, p.35, "Peculiar Morphologies of Four IRAS Galaxies"

Chu, Y-H., Kennicutt, Jr., R.C 1991, IAU Symposium 148, eds. R. Haynes, D. Milne (Dordrecht,Kluwer), p.97, "Fast SheUs and X-Ray Emission in 30 Doradus: SNRS and Superbubbles"

Carta, J.J., Lapasset, E. 1990, Rev. Mexicana Astr. Astrof. 21, p.351, "The Structure of the HR Diagramfor Population I Red Giants of Intermediate Mass"

Carta, J.J., Lapasset, E., Bosio, M.A. 1991, MNRAS, 249, p.193, "Membership, Fundamental Parametersand Luminosity Function of the Open Custer NGC 5662"

Clement, CM., Kinman,T.D., Suntzeff, N.B. 1991, ApJ, 372, p.273, "Two Double-Mode RR Lyrae Starsin the Field"

Clowes, R.G., Campusano, L.E. 1991, MNRAS, 249, p.218, "A 100-200 Mpc Group of Quasars"

Colina, L., Sparks, W.B., Macchetto, F. 1991, ApJ, 370, p.102, "IC 5063: A Merger Remnant with HiddenLuminous Active Nucleus"

Conti, P.S., Fitzpatrick, E. 1991, ApJ, 373, p.100, "DD13: A Very Young and Heavily Reddened Early0 Star in the Large MageUanic Coud"

Costa, E. 1990, PASP, 102, p.789, "Coordinates and RI Photometry of LMC Carbon Stars"

C6te\ P., et al. 1991, AJ, 101, p.1681, "Baade-Wessehnk Radii for NGC 1866 Cepheids"

Cowley, A.P., et al. 1990, Accretion Powered Compact Binaries, ed. C.W. Mauche (Cambridge U. Press),p.7, "An EcUpsing Black Hole (?) in the LMC"

Cowley, A.P., Hartwick, F.D.A. 1991, ApJ, 373, p.80, "The Halo of the Large MageUanic Cloud:Kinematics of the CH Stars"

Cowley, A.P., et al. 1991, ApJ, 373, p.228, "The Near-Infrared Spectra of the Low-Mass X-Ray Binariesand Related Objects"

Crocker, D.A., Buta, R. 1990, IAU Symposium 146, eds. F. Combes, F. Casoli (Dordrecht, Kluwer),p.254, "A Selection of Galaxies from the CSRG: Imaging of Outer Rings and Pseudorings"

Crotts, A.P.S., Heathcote, S.R. 1991, Nature, 350, p.683, "Velocity Structure of the Ring Nebula AroundSupernova 1987A"

Cudwordi, K.M., Rees, R.F. 1991, PASP, 103, p.470, "Scales and Distortion Constants of Four SouthernTelescopes"

Da Costa, G.S., Armandroff,T.E. 1990, AJ, 100, p.162, "StandardGlobular Cluster Giant Branches in theMlt (V-l)0 Plane"

Da Costa, G.S. 1991, IAU Symposium 148, eds. R. Haynes, D. Milne (Dordrecht, Kluwer), p.183,"The Age-Abundance Relations and Age Distributions for the Star Custers of the MageUanic Couds"

Danks, A.C., Perez, M.R., Altner, B. 1990, ESO/CTIO Workshop on Bulges of Galaxies, eds. B.J. Jarvis,D.M. Temdrup (ESO), p.243, "Multiwavelength Studies of Early Type Galaxies"

Daou, D., et al. 1990, ApJ, 364, p.242, "Spectroscopic Studies and Atmospheric Parameters of PulsatingDA White Dwarf (ZZ Ceti) Stars"

Demers, S., et al. 1991, IAU Symposium 148, eds. R. Haynes, D. Milne (Dordrecht, Kluwer), p.473,"Radial Velocities of Clusters Between the Magellanic Clouds"

DcPoy, D.L. 1990, ASP Conf. Series, 14, ed. R. Elston (ASP), p.219, "Infrared Images and [Fe II] Spectraof the Galactic Center"

DePoy, D.L., et al. 1990, PASP, 102, p. 1433, "The Cerro Tololo Inter-American Observatory InfraredSpectrometer"

DePoy, D.L., et al. 1990, ApJ, 356, p. L55, "The Luminosity Function in NGC 2023"

DePoy, D.L., Sharp, N.A. 1991, AJ, 101, p.1324, "High Resolution Infrared Imaging of the GalacticCenter"

Diaz, P.M., Steiner, J.E. 1990, Rev. Mexicana Astron. Astrof, 21, p.369, "Photometry of Nova Muscae1983"

Dickman, R.L., Jarret, T.H., Herbst, W. 1990, SubmiUimetre Astronomy, eds. G.D.Watt, A.S. Webster(Dordrecht, Kluwer), p. 171, "Probing the Lower Main Sequence with Molecular Couds"

Djorgovski, S., et al. 1990, AJ, 100, p.599 "A Rich, Nearby Galaxy Custer In Sagittarius"

Djorgovski, S., Weir, N., Meylan, G. 1990, Gravitational Lensing, eds. Y. MeUier, B. Fort, G. Soucail(Springer-Verlag), p.108, "Application of Image Processing Techniques in a Search for GravitationalLenses and Quasar Pairs"

Djorgovski, S. 1991, ASP Conference 13, ed. K. Janes (ASP), p.112, "The Manifold of Globular Clusters"

Djorgovski, S., et al. 1991, ApJ, 372, p. L41, "Modification of SteUar Populations in Post-Core-CoUapseGlobular Clusters"

Dottori, H. 1990, ESO/CTIO Workshop on Bulges of Galaxies, eds. B.J. Jarvis, D.M. Temdrup (ESO),p.299, "Circumnuclear Regions of Star Formation: A Lindblad Resonance Within the Bulge"

Eggen, O. 1990, AJ, 100, p.1159, "Astrometric and Astrophysical Discontinuities Between the GalacticOld Disk and Halo Stellar Populations"

Eggen, O., Iben, I. Jr. 1991, AJ, 101, p.1377, "First Giant Branch and Asymptotic Giant Branch Stars inNearby Aggregates"

Elias, J.H., DePoy, D.L., Gregory, B. 1990, ASP Conference 14, ed. R. Elston (ASP), p.174, "InfraredObservations of SN 1987A"

Feinstein, C, et al. 1990, A&A, 239, p.90, "A CCD Morphological Study of the Starburst GalaxyNGC 7552"

Ferraro, F.R., et al. 1990, A&AS, 84, p.59, "CCD-Photometry of the Galactic Globular-Cluster NGC 2808"

Fitzgerald, M.P., Harris, G.L.H., Reed, B.C. 1990, PASP, 102, p.865, "The Moderately Young OpenCluster NGC 2353"

Franx, M., rUingworth, G. 1990, ApJ, 359, p. L41, "Color Gradients in Elliptical Galaxies"

Friel, E.D., Geisler, D. 1990, ESO/CTIO Workshop on Bulges of Galaxies, eds. B.J. Jarvis.D.M. Temdrup(ESO), p. 163, "Washington CCD Photometry of Bulge Globular Clusters"

Friel, E.D., Geisler, D. 1991, AJ, 101, p. 1338, "Washington CCD Photometry of the Disk Globular CusterNGC 5927 and NGC 6496"

Frisch, P.C, Sembach, K., York, D.G. 1990, ApJ, 364, p.540, "Studies of the Local InterstellarMedium. VIII. Morphology and Kinematics of the Diffuse IntersteUar Couds Toward Orion"

Frogel, J.A., Blanco, V.M. 1990, ApJ, 365, p.168, "The Large MageUanic Coud Bar West Field"

Gamett, D.R., et al. 1991, ApJ, 373, p.458, "HE II Emission in Extragalactic H II Regions"

Geisler, D., Friel, E.D. 1990, ESO/CTIO Workshop on Bulges of Galaxies, eds. B.J. Jarvis.D.M. Temdrup(ESO), p.77, "Abundance Distribution of Baade's Window Giants"

Geisler, D., et al. 1991, IAU Symposium 148, eds. R. Haynes, D. Milne (Dordrecht, Kluwer), p.341,"Metal Abundances of MageUanic Couds Custers"

Gezari, D., Btitz, L. 1990, SubmiUimetre Astronomy, eds. G.D. Watt and A.S. Webster (Dordrecht,Kluwer), p.173, "1.0-mm Continuum,12CO, 13CO and C180 Mapping of the NGC 6334 Complex andComparison with IRAS Observations"

Gilliland, R.L., et al. 1991, AJ, 101, p.541, "Time-Resolved CCD Photometry of an Ensemble of Starsin the Open Cluster M67"

Girardi, L., Pastoriza, M. 1990, ESO/CTIO Workshop on Bulges of Galaxies, eds. B.J. Jarvis,D.M. Temdrup (ESO), p.305, "Gas and SteUar Spectra of Some Normal and Seyfert Galaxies"

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Tyson, N.D., Rich, R.M. 1991, ApJ, 367, p.547, "Radial Velocity Distribution and Line Strengths of 33Carbon Stars in the Galactic Bulge"

Vacca, W.D., Conti, P.S. 1991, IAU Symposium 143, eds. K.A. van der Hucht, B. Hidayat (Dordrecht,Kluwer), p.656, "Wolf-Rayet Galaxies"

VandenBerg, D.A., Bolte, M., Stetson, P.B. 1990, AJ, 100, p.445, "Measuring Age Differences AmongGlobular Custers Having Similar MetaUicities: A New Method and First Results"

Vasquez, R.A., Feinstein, A. 1990, A&AS, 86, p.209, "The Open Custer Tr 18"

Vasquez, R.A., Feinstein, A. 1991, A&AS, 87, p.383, "The Young Open Custer NGC 5606"

Vermes, S., et al. 1991, ApJ, 372, p. L37, "The Binary Feige 24: The Mass, Radius, and GravitationalRedshift of the DA White Dwarf'

Wakamatsu, K.I., Nishida, M.T. 1991, PASP, 103, p.392, "A Ring Galaxy in Canes Venatici and RelatedRing Galaxies"

14

Walbom, N.R., Fitzpatrick, E.L., PhiUips, M.M. 1991, IAU Symposium 143, eds. K.A. van der Hucht,B. Hidayat (Dordrecht, Kluwer), p.505, "New Observations of LBV Environments"

Walker, A.R. 1990, ASP Conference 11, eds. C. Cacciari, G. Cementini (ASP), p.149, "The RR Lyraesin the Oudying LMC Custer NGC 1841"

Walker, A.R. 1990, AJ, 100, p.1532, "The LMC Custer NGC 1841: Photometry of the RR Lyraes, andColor Magnitude Diagram"

Walker, A.R. 1991, IAU Symposium 148, eds. R. Haynes, D. Milne (Dordrecht, Kluwer), p.307,"RR Lyrae Stars in the MageUanic Couds"

Walker, A., Sharpies, R., Cropper, M. 1990, ESO/CTIO Workshop on Bulges of Galaxies, ed. B.J. Jarvis,D.M. Temdrup (ESO), p.99, "Kinematics of the Baade Window Late M Giants"

Wallerstein, G., Balick, B. 1990, MNRAS, 245, p.701, "Long Slit Observations of Emitting Gas in theVela Supernova Remnant"

Ward, M.J., DePoy, D.L., Aspin, C. 1990, ASP Conference 14, ed. R. Elston (ASP), p.76, "InfraredImages of AGN"

Warren, S.J., Hewett, P.C, Osmer, P.S. 1991, ApJS, 76, p.23, "A Wide-Field Multicolor Survey for High-Redshift Quasars, z > 2.2. II. The Quasar Catalog"

Weaver, K.A. Wilson, A.S., Baldwin, J.A. 1991, ApJ, 366, p.50, "Kinematics and Ionization of ExtendedGas in Active Galaxies. VI. The Seyfert 2 Galaxy NGC 1386"

Welch, D.L. et al. 1990, ASP Conference 11, eds. C. Cacciari, and G. Cementini (ASP), p.233,"NGC 1866: New Variables, New Constraints on the Instability Strip"

Welch, D.L. et al. 1991, AJ, 101, p.490, "The Variable Stars of NGC 1866"

Welch, D.L. etal. 1991, IAUSymposium 148, eds. R. Haynes, D. Milne (Dordrecht, Kluwer), p.384, "TheVariable Star Population of NGC 1866"

Weller, W.G., Anthony-Twarog, B.J., Twarog, B.A. 1991, ASP Conference 13, ed. K. Janes (ASP), p. 302,"CCD Photometry with a Schmidt Telescope"

Wheeler, J.C. 1990, Supernovae, eds. J.C. Wheeler, et al., Sixth Jemsalem Winter School for TheoreticalPhysics, p.l, "Introduction to Supernovae"

Whitford, A.E., Temdrup, D.M., Frogel, J.A. 1990, ESO/CTIO Workshop on Bulges of Galaxies,eds. B.J. Jarvis, D.M. Temdrup(ESO), p.19, "Infrared Spectrophotometry of Baade's Window M Giants"

Whitmore, B.C., et al. 1990, AJ, 100,p.1489, "New Observations and a Photographic Adas of Polar-RingGalaxies"

Whittet, D.C., Prusti, T., Wesselius, P.R. 1991, MNRAS, 249, p.319, "A Study of the Chamaeleon I DarkCloud and T-Association - III. Near-Infrared Photometry of IRAS-Selected Field Stars"

15

WUcots, E.M., Hodge, P. 1991, IAU Symposium 148, eds. R. Haynes, D. Mime (Dordrecht, Kluwer),p.226, "Faint HII Regions in the MageUanic Couds"

WiUiams, R.E. 1990, IAU CoUoquium 122, eds. A. CassateUa, R. Viotti (Berlin, Springer-Verlag), p.215,"The Ionization of Novae Ejecta"

Wing, R., MacConneU, D.J. 1990, ESO/CTIO Workshop on Bulges of Galaxies, eds. B. Jarvis,D. Temdrup (ESO), p.337, "On the CN Strength of a Luminous Red Variable in the Bulge of M337"

Winge, C, Pastoriza, M.G., Storchi-Bergmann, T. 1990, Rev. Mexicana Astron. Astrof, 21, p.177,"On the Low State of Activity of NGC 3783"

Winge, C, Storchi-Bergmann, T., Pastoriza, M.G. 1990, ESO/CTIO Workshop on Bulges of Galaxies,eds. B.J. Jarvis, D. Temdrup (ESO), p.325, "The Bulge SteUar Population of NGC 3783"

Woosley, S.E. 1990, Supernovae Workshop, ed. S.E. Woosley (New York, Springer-Verlag), p.307,"Supernova 1987A - Its Light Curve, Composition, and Pulsar"

Wycoff, S., Tegler, S.C, Engel, L. 1991, ApJ, 367, p.641, "Nitrogen Abundance in Comet Halley"

YahU, A., et al. 1991, ApJ, 372, p.380, "A Redshift Survey of IRAS Galaxies. II. Methods forDetermining Self-Consistent Velocity and Density Fields"

Yusef-Zadeh, F., et al. 1990, IAU Symposium 140, eds. R. Beck, P.P. Kronberg, R. Wielebinski(Dordrecht, Kluwer), p.329, "Detection of Synchrotron Emission from a Unique Herbig-Haro Object inOrion"

Zickgraf, F., et al. 1990, PASP, 102, p.920, "CCD Photometric UBVR Sequences from M83 andNGC 5128"

Zinnecker, H., et al. 1991, IAU Symposium 148, eds. R. Haynes, D. Milne (Dordrecht, Kluwer), p.228,"Infrared Imaging of Intermediate Age LMC/SMC Custers"

16

APPENDIX C

Kitt Peak National ObservatoryJuly 1990 to June 1991 Publications List

In the period 1 July 1990 through 30 June 1991, a total of 523 visiting scientists used the telescopes onKitt Peak. A total of 128 visiting scientists used the KPNO data reduction faciUties. A total of 334publications were written by visitors and staff.

Aaronson, M. et al. 1990, ApJS, 73, p. 841, "Northern Milky Way Carbon Stars: New Candidates, JHKPhotometry, and Radial Velocities"

Abt, H.A. 1990, PASP, 102, p. 1161, "Publication Characteristics of Members of the AmericanAstronomical Society"

Abt, H.A. 1990, Current Contents, 33, #39, p. 5, "The Use of Publication Studies to Affect Policies andAttitudes in Astronomy. Part 1"

Abt, H.A. 1990, Current Contents, 33, #40, p. 5, "The Use of Publication Studies to Affect Policies andAttitudes in Astronomy. Part 2"

Abt, H.A., Gomez, A.E., Levy, S.G. 1990, ApJS, 74, p. 551, "The Frequency and Formation Mechanismof B2-B5 Main-Sequence Binaries"

Abt, H.A., Wang, R., Cardona, O. 1991, ApJ, 367, p. 155, "Spectroscopic Binaries in the Orion NebulaCluster"

Adelman, S.J., Philip, A.G.D. 1990, A&A, 238, p. Ill, "Elemental Abundances of the Mercury-Manganese Stars HR 4817 and x Lupi"

Adelman, S.J., PhiUp, A.G.D. 1990, CCDs in Astronomy. II., ed. A.G.D. Philip, D.S. Hayes, S.J. Adelman(Schenectady, NY, Davis Press), p. 3, "Using KPNO Coude" Exposures to Study Field Horizontal-BranchStars"

Adelman, S.J., PhiUp, A.G.D. 1990, MNRAS, 247, p. 132, "Elemental Abundances of the FieldHorizontal-Branch Stars HD 86986, 130095 and 202759"

Adelman, S.J., Philip, A.G.D. 1990, PASP, 102, p. 842, "A Comparison of KPNO CCD and CoaddedDAO Photographic Spectroscopic Data"

Allen, L.E., Young, J.S. 1990, The Interstellar Medium in External Galaxies: Summaries of ContributedPapers, ed. D.J. HoUenbach, H.A. Thronson, Jr. (NASA), p. 321, "Global and Radial Variations in theEfficiency of Massive Star Formation Among Galaxies"

Anthony-Twarog, B.J., et al. 1991, AJ, 101, p. 1902, "Ca n H and K Filter Photometry on the uvbySystem. I. The Standard System"

Armandroff, T.E., DaCosta, G.S. 1991, AJ, 101, p. 1329, "MetaUicities for Old SteUar Systems From CaII Triplet Strengths in Member Giants"

Armandroff, T.E., DaCosta, G.S. 1991, ASP Conference 13, ed. K. Janes (ASP), p. 543, "Globular CusterMetaUicities from Ca II Triplet Strengths in Custer Giants"

Armus, L., Heckman, T.M., Miley, G.K. 1990, ApJ, 364, p. 471, "The Optical Emission-Line Nebulae ofPowerful Far-Infrared Galaxies"

Aumann, H.H., Probst, R.G. 1991, ApJ, 368, p. 264, "Search for Vega-Like Nearby Stars with 12 MicronExcess"

BalceUs, M., Stanford, S.A. 1990, ApJ, 362, p. 443, "A Counter-rotating Core in the Merger RemnantCandidate NGC 3656 (ARP 155)"

Balick, B., et al. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 167, "The Distribution and Excitationof H-, in Planetary Nebulae"

Bally, J., Lane, A.P. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 273, "Shocked MolecularHydrogen Associated with Herbig-Haro Objects and Molecular Outflows: The Cepheus-A Flow"

Barden, S. C, Rudeen, A. 1990, SPIE, 1235, p. 729, "The Kitt Peak National Observatory Fiber ActuatorDevice"

Barker, T. 1991, ApJ, 371, p. 217, "The Ionization Structure of Planetary Nebulae. X. NGC 2392"

Batuski, D.J., et al. 1991, AJ, 101, p. 1983, "Galaxy and Cluster Redshift Observations in the Sextans-LeoRegion"

Baum, S.A., Heckman, T., van Breugel, W. 1990, ApJS, 74, p. 389, "Long-Slit Optical Spectroscopy ofEmission-Line Nebulae in Radio Galaxies: The Data"

Beichman, C.A., Ridgway, S. 1991, Physics Today, 44, p. 48, "Adaptive Optics and Interferometry"

Belton, M.J.S. 1990, Icarus, 86, p. 30, "Rationalization of Comet Halley's Periods"

Belton, M.J.S. 1991, IAU CoUoq. 116, ed. R.L. Newbum, Jr., et al. (Dordrecht, Kluwer), p. 691,"Characterization of the Rotation of Cometary Nuclei"

Bcrshady, M., et al. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 9, "Optical-Infrared Colors of aComplete Sample of Field Galaxies with Spectroscopic Redshifts"

Bianchi, L., Jurcsik, J., Fekel, F.C. 1991, A&A, 245, p. 604, "The Nature of HD 220140 From Opticaland IUE Observations"

Binney, J.J., Davies, R.L., Iltingworth, G.D. 1990, ApJ, 361, P. 78, "Velocity Mapping and Models of theElliptical Galaxies NGC 720, NGC 1052, and NGC 4697"

Black, J.H., et al. 1990, ApJ, 358, p. 459, "IntersteUar Absorption Lines Toward NGC 2264 and AFGL2591: Abundances of H2, H3+, and CO"

Bohannan, B., et al. 1990, ApJ, 365, p. 729, "Photospheres of Hot Stars. IV. Spectral Type 04"

Boisseau J.R., Wheeler, J.C. 1991, AJ, 101, p. 1281, "The Effect of Background Galaxy Contaminationon the Absolute Magnitude and Light Curve Speed Cass of Type la Supernovae"

Bond, H.E., CiarduUo, R. 1990, ASP Conference 11, ed. C. Cacciari, G. Cementini (ASP), p. 529,"Pulsations of Central Stars of Planetary Nebulae"

Bopp, B.W., Parsons, S.B., Dempsey, R.C. 1991, PASP, 103, p. 444, "Optical and UltravioletSpectroscopy of Three F + B Binary Stars"

Boroson, T.A. 1990, ApJ, 360, p. 465, "New Observations of NGC 1275: PeculiarVelocities in the High-Velocity System"

Boroson, T.A., et al. 1991, ApJ, 370, p. L19, "The Appearance of a New Redshift System in Markarian231"

Boroson, T.A., Thompson, LB. 1991, AJ, 101, p. Ill, "Color Distributions in Early Type Galaxies. III.Radial Gradients in Spectral Features"

Bothun, G.D., et al. 1990, ApJ, 360, p. 427, "Discovery of a Second Giant Low Surface BrighmessGalaxy: Further Confirmation of Slowly Evolving Disk Galaxies"

Boughn, S.P., Kuhn, J.R., Uson, J.M. 1990, IAU Symp. 139, ed. S. Bowyer, C Leinert (Dordrecht,Kluwer), p. 357, "CCD Observation of Diffuse Light in the Rich Custer A2029"

Boyle, R.P., et al. 1990, A&AS, 84, p. 1, "CCD Photometry in the Vilnius Photometric System. I. Regionin Lyra"

Boyle, R.P., et al. 1990, A&AS, 86, p. 395, "CCD Photometry in the Vilnius Photometric System.II. Region in Sagitta"

Burke, B.F. 1990, Gravitational Lensing, ed. Y. MeUier, B. Fort, G. Soucail (Berlin, Springer-Verlag),p. 127, "The MIT Search Program for Gravitational Lenses"

Burrows, C.J., et al. 1991, ApJ, 369, p. L21, "The Imaging Performance of the Hubble Space Telescope"

Bushouse, H.A., Werner, M.W. 1990, ApJ, 359, p. 72, "Near-Infrared Imaging of Interacting Galaxies"

Bushouse, H., et al. 1990, IAU Colloq. 124, ed. J.W. Sulentic, W.C. Keel, CM. Telesco (NASA), p. 285,"A Multiwavelength Survey of Interacting Galaxies"

Bushouse, H. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 50, "The Near-Infrared Morphology ofInteracting Galaxies"

Caillault, J-P. 1990, PASP, 102, p. 989, "The M-Dwarf Contribution to the Diffuse Soft X-RayBackground Revisited"

CaiUault, J-P., Patterson, J. 1990, AJ, 100, p. 825, "On the Mass-Radius Relation of Late M Dwarfs"

Carini, M.T., MiUer, H.R., Goodrich, B.D. 1990, AJ, 100, p. 347, "The Timescales of the OpticalVariability of Blazars. I. OQ 530"

Carini, M.T., et al. 1991, AJ, 101, p. 1196, "The Timescales of the Optical Variability of Blazars.II. AP Librae"

Carney, B.W., FuUton. L.K., TrammeU, S.R. 1991,101, p. 1699, "The Distant Globular Custer NGC 6229and Its Relation to Other Outer Halo Custers"

Chaboyer, B., Vader, J.P. 1991, PASP, 103, p. 35, "Peculiar Morphologies of Four IRAS Galaxies"

Chambers. K.C., Miley, G.K., van Breugel, W.J.M. 1990, ApJ, 363, p. 21, "4C 41.17: A Radio Galaxyat a Redshift of 3.8"

Chen, W.P., et al. 1990, ApJ, 357, p. 224, "Discovery of Five Pre-Main-Sequence Binaries in Taurus"

Christian, C.A., Crabtree, D.R., Davis, L.E. 1990, CCDs in Astronomy. II., ed. A.G.D. Philip, D.S. Hayes,S.J. Adelman (Schenectady, NY, Davis Press), p. 99, "Photometry Routines in IRAF"

Chnstou, J.C. 1990, SPEE, 1237, p. 424, "Application of a Deconvolution Technique to Enforce a PrioriObject Constraints to 2-D IR Speckle Data"

Christou, J.C, et al. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 133, "High Spatial ResolutionImaging of CircumsteUar Envelopes in the Near Infrared"

CiarduUo, R., Tamblyn, P., PhiUips, A.C. 1990, PASP, 102, p. 1113, "A Search for Novae in M 31Globular Clusters"

Clement, CM., Kinman, T.D., Suntzeff, N.B. 1991, ApJ, 372, p. 273, "Two Double-Mode RR Lyrae Starsin the Field"

Craine, E.R., Engel, J.R., Probst, R.G. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 319, "InfraredArray Photometry of a Select Group of Cool Dwarf Star Candidates"

Crawford, D.L. 1991, ASP Conference V.17, ed. D. L. Crawford (ASP), p. 7, "Light PoUution - AProblem For All of Us"

Crocker, D.A. 1991, ASP Conference 13, ed. K. Janes (ASP), p. 253, "HB Theory and Observations: NewData on M3 and Ml3"

Da Costa, G.S., Armandroff, T.E. 1990, AJ, 100, p. 162, "Standard Globular Custer Giant Branches inthe (MJt(V-I)0) Plane"

DePoy, D.L., Sharp, N.A. 1991, AJ, 101, p. 1324, "High Resolution Infrared Imaging of the GalacticCenter"

De Robertis, M.M., Yee, H.K.C. 1990, AJ, 100, p. 84, "Optical Nuclear Activity in the Radio Galaxy3C 465"

Dettmar, R.-J., et al. 1990, The IntersteUar Medium in External Galaxies: Summaries of ContributedPapers, ed. D.J. HoUenbach, H.A. Thronson, Jr. (NASA), p. 172, "The Diffuse Ionized Interstellar MediumPerpendicular to the Plane of NGC 891"

Dewdney, P.E., et al. 1991, ApJ, 370, p. 243, "IRAS 23545+6508, A Dissociating Star: Prototype for aNew Observational Class?

De Young, D.S. 1991, ApJ, 371, p. 69, "The Deflection of Cosmic Jets"

De Young, D.S. 1991, Science, 252, p. 389, "Astrophysical Jets"

Dickman, R.L., Jarrett, T.H., Herbst, W. 1990, SubmiUimeter Astronomy, ed. G.D. Watt, A.S. Webster(Dordrecht, Kluwer), p. 171, "Probing the Lower Main Sequence with Molecular Clouds"

Doinidis, S.P., Beers, T.C 1990, PASP, 102, p. 1392, "Photoelectric UBV Photometry of Northern StarsFrom the HK Objective-Prism Survey"

Donahue, M., et al. 1990, The Interstellar Medium in External Galaxies: Summaries of Contributed Papers,ed. D.J. HoUenbach, H.A. Thronson, Jr. (NASA), p. 196, "Optical Emission From Cooling Flows inDistant X-Ray Clusters of Galaxies"

Dougados, C, et al. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 258, "Sub-Arcsecond Imaging ofthe Orion IRc2 Region"

Dougados, C, et al. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 152, "Near Infrared HighResolution Polaro-Imaging of OH231.8+4.2"

Drissen, L., Shara, M.M., Moffat, A.F.J. 1991, AJ, 101, p. 1659, "Ring Nebulae Around Wolf-Rayet Starsin M33"

Dumey, B.R., De Young, D.S., Passot, T.P. 1990, ApJ, 362, p. 709, "On the Generation of the SolarMagnetic Field in a Region of Weak Buoyancy"

Dyck, H.M., et al. 1990, SPIE, 1237, p. 31, "Recent Progress on the Infrared Michelson Array"

Eaton, J.A. 1990, MNRAS, 247, p. 62, "The Long-Period Binary UU Cancri as a System that hasReversed its Mass Ratio"

Eisenhardt, P., et al. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 100, "Infrared Images of HighRedshift Radio Galaxies"

Ellingson, E.. Yee, H.K.C., Green, R.F. 1991, ApJS, 76, p. 455, "Quasars and Active Galactic Nuclei inRich Environments. I. Fields Surrounding Optically Faint Quasars"

Ellingson, E., Yee, H.K.C., Green, R.F. 1991, ApJ, 371, p. 49, "Quasars and Active Galactic Nuclei inRich Environments. II. The Evolution of Radio-Loud Quasars"

Elston, R., Maloney, P. 1990, ApJ, 357, p. 91, "SpatiaUy Resolved Near-Infrared Spectroscopy of NGC6240"

Elston, R., et al. 1991, ApJ, 373, p. L39, "Emission from the r=2 Damped Lya Absorber TowardQ1215+333"

Elston, R., Rieke, G., Rieke, M. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 3, "The Colors of2 urn Selected Galaxies"

Federici, L., Fusi Pecci, F., Marano, B. 1990, A&A, 236, p. 99, "Kinematics of a Sample of GlobularClusters in the Halo and the Mass of M31"

Federici, L., et al. 1991, ASP Conference 13, ed. K. Janes (ASP), p. 388, "The Globular Custer Systemand the Mass of M31: A Progress Report"

Fekel, F.C. 1991, AJ, 101, p. 1489, "ChromosphericaUy Active Stars. VIII. HD 155638=V792 Herculis:Observational Constraints on Evolutionary Theory"

Fesen. R.A., Becker, R.H. 1991, ApJ, 371, p. 621, "New Cues to the Cassiopeia A Supernova Progenitor"

Fich, M., Silkey, M. 1991, ApJ, 366, p. 107, "Abundances in H II Regions at the Edge of the Galaxy"

Filippenko, A.V., Porter, A.C., Sargent, W.L.W. 1990, AJ, 100, p. 1575, "The Type Ic (Helium-Poor lb)Supernova 1987M: Transition to the Supernebular Phase"

Fischer, J., Smith, H. A., Glaccum, W. 1991, ASP Conference 14. ed. R. Elston (ASP), p. 63, "Fabry-PerotImaging Spectroscopy of Interacting and Merging Galaxies: NGC 3690 and NGC 6240"

Foss, D., Wade, R.A., Green, R.F. 1991, ApJ, 374, p. 281, "Limits on the Space Density of DoubleDegenerates as Type la Supernova Progenitors"

Fowler, A.M., Gatley, L, MerriU, K.M. 1990, SPIE, 1341, p. 52, "A 256 x 256 PtSi Hybrid Array forAstronomy Applications"

Freedman, W.L., Wilson, CD., Madore, B.F., ApJ, 372, p. 455, "New Cepheid Distances to NearbyGalaxies Based on BVRI CCD Photometry II. The Local Group Galaxy M33"

Friel, E.D., Janes, K.A. 1991, ASP Conference 13, ed. K. Janes (ASP), p. 569, "MetaUicities andKinematics of Old Open Clusters"

Frisch, P.C, Sembach, K., York, D.G. 1990, ApJ, 364, p. 540, "Studies of the Local Interstellar Medium.VIII. Morphology and Kinematics of the Diffuse IntersteUar Couds Toward Orion"

Furton, D.G., Witt, A.N. 1990, ApJ, 364, p. L45, "The Spatial Distribution of Extended Red Emission inthe Planetary Nebula NGC 7027"

GaUagher III, J.S., et al. 1991, ApJ, 371, p. 142, "Far-Infrared Properties of NGC 6822"

Garden, R.P., et al. 1991, ApJ, 366, p. 474, "A Spectroscopic Study of the DR 21 Outflow Source. II. TheVibrational H2 Line Emission"

Garden, R.P., et al. 1991, ApJ, 374, p. 540, "A Spectroscopic Study of the DR 21 Outflow Source.III. The CO Line Emission"

Garmany, C. D., Vacca, W.D. 1991, PASP, 103, p. 347, "New Spectral Classifications for O-Type Starsin the Northern Hemisphere"

Gamavich, P.M., et al. 1990, ApJ, 365, p. 696, "A Study of the Eclipsing Cataclysmic Variable Lanning90"

Gadey, I., et al. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 230, "The Luminosity Function inRegions of Massive Star Formation"

Gatley, I. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 339, "Concluding Remarks"

Gavazzi, G., BoseUi, A., Kennicutt, R. 1991, AJ, 101, p. 1207, "Multifrequency Windows on SpiralGalaxies. I. UBV and Ha Aperture Photometry"

Gillett, F.C., Houck, J.R. 1991, Physics Today, 44, p. 32, "The Decade of Infrared Astronomy"

GiUiland, R.L., et al. 1991, AJ, 101, p. 541, "Time-Resolved CCD Photometry of an Ensemble of Starsin the Open Cluster M67"

Gilroy, K.K., Brown, J.A. 1991, ApJ, 371, p. 578, "Carbon Isotope Ratios Along the Giant Branchof M67"

Graham, J.A., Heyer, M.H. 1990, PASP, 102, p. 972, "New Optical Features in L1551 and HH30"

Green, P.J., Margon, B. 1990, PASP, 102, p. 1372, "Spectroscopy of Faint Halo Carbon Stars"

Halbedel, E.M. 1991, PASP, 103, p. 310, "Photometric Variability fortheVV Cephei-Like StarHR 8164"

Halbedel, E.M. 1991, PASP, 103, p. 452, "HDE 229189: A Variable Ae Star in the Field of NGC 6910"

HaU, J.C, et al. 1990, ApJ, 358, p. 610, "Fiber-Optic EcheUe CCD Observations of SS Bootis"

Halpem, J.P. 1990, ApJ, 365, p. L51, "Line Emission From Another Relativistic Accretion Disk: 3C 332"

Haniff, C.A., et al. 1990, SPIE, 1237, p. 259, "Diffraction-Limited Imaging at IR Wavelengths UsingAperture Masks and FuUy-FiUed Apertures"

Hardie, R.H., et al. 1990, J. Ap. Astr., 11, p. 277, "UBV Photometry of the Ap Variable UZ Psc = HD10783"

Harris, W.E. 1990, PASP, 102, p. 949, "A Comment on Image Detection and the Definition of LimitingMagnitude"

Hartman, L., et al. 1991, AJ, 101, p. 1050, "A Proper Motion Survey for Pre-Main-Sequence Stars inTaurus-Auriga"

Hayashi, S.S., et al. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 285,"IR and Radio Images of StarForming Regions: Dissipation of the Placental Coud"

Hayes, J.J.E., Bhattacharya, B. 1990, IAU CoUoq. 124, ed. J.W. Sulentic, W.C. Keel, CM. Telesco(NASA), p. 195, "The cD Galaxy in AbeU Custer 1775"

Heckman, T.M., Armus, L., Miley, G.K. 1990, ApJS, 74, p. 833, "On the Namre and Implications ofStarburst-Driven Galactic Superwinds"

Heckman, et al. 1991, ApJ, 370, p. 78, "SpatiaUy Resolved Optical Images of High-Redshift Quasi-StellarObjects"

Hessman, F.V., et al. 1991, ApJ, 370, p. 384, "The High State of the FU Orionis Variable Z CanisMajoris"

Hester, J.J., et al. 1991, ApJ, 369, p. L75, "Ionization Fronts and Shocked Flows: The Structure of theOrion Nebula at 0.1 Arcsec"

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Tamura, M., et al. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 291, "Near Infrared ImagingPolarimetry of Star Forming Regions"

Tamura, M., et al. 1991, ApJ, 371, p. 131, "Near-Infrared Long-Slit Spectra of NGC 1068"

Tamura, M., et al. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 88, "Near Infrared Long Slit Spectraof NGC 1068"

Tamura, M., et al. 1991, ApJ, 374, p. L25, "Two Micron Morphology of Candidate Protostars"

Tanaka, M, Hasegawa, T. Gadey, I. 1991, ApJ, 374, p. 516, "Infrared Fluorescence of H2 in NGC 6240:A Starburst Origin for the H2 Luminosity"

Telesco, CM., et al. 1991, ApJ, 369, p. 135, "Infrared Mapping of M82: A Starburst in an Edge-OnBarred Galaxy"

Temdrup, D.M., Frogel, J.A., Whitford, A.E. 1990, ApJ, 357, p. 453, "Galactic Bulge M Giants. III. Near-Infrared Spectra and Implications for the SteUar Content of E and SO Galaxies"

Thompson, A.B., Massey, P. 1991, ASP Conference 13, ed. K. Janes (ASP), p. 180, "Massive Stars inCygnus OB2"

Tonry, J.L. 1990, Dynamics ano interactions of Galaxies, ed. R. Wielen (Beriin, Springer-Verlag), p. 275,"Rummaging Through EUiptical Galaxies"

Tonry, J.L., Ajhar, E. A., Luppino, G.A. 1990, AJ, 100, p. 1416, "Observations of Surface-BrightnessFluctuations in Virgo"

Tonry, J.L. 1991, ApJ, 373, p. LI, "Surface Brighmess Fluctuations: A Bridge From M31 to the HubbleConstant"

Torres-Peimbert, S., Peimbert, M., Pefia, M. 1990, A&A, 233, p. 540, "Planetary Nebulae with a HighDegree of Ionization: NGC 2242 and NGC 4361"

Tripp, T.M., Green, R.F., Bechtold, J. 1990, ApJ, 364, p. L29, "WE Observations of PG 1115+080: TheHe I Gunn-Peterson Test and a Search for the Lensing Galaxy"

18

Tsuji, T. 1991, A&A, 245, p. 203, "High Resolution Spectroscopy of CO in the Infrared Spectra of CoolStars"

Udalski, A.. Kaluzny, J. 1991, PASP, 103, p. 198, "CCD Photometry of the X-Ray Nova V404 CygniAfter the 1989 Outburst"

Uomoto, A. 1991, AJ, 101, p. 1275, "Late-Time Spectroscopy of Two Supernovas: The Type II 1980Kand the Type V 1986J"

Uson, J.M, Boughn, S.P., Kuhn, J.R. 1990, Science, 250, p. 539, "The Central Galaxy in AbeU 2029: AnOld Supergiant"

Uson, J.M., Boughn, S.P., Kuhn, J.R. 1991, ApJ, 369, p. 46, "Diffuse Light in Dense Custers of Galaxies.I. /?-Band Observations of AbeU 2029"

Uson, J.M., Boughn, S.P. 1991, ApJ, 369, p. 38, "Large-Aperture BVRJK Photometry of Rich AbeUClusters: Constraints on Dark Matter"

VandenBerg, D.A., Bolte, M., Stetson, P.B. 1990, AJ, 100, p. 445, "Measuring Age Differences AmongGlobular Custers Having Similar MetaUicities: A New Method and First Results"

Van der Marel, R.P., Binney, J., Davies, R.L. 1990, MNRAS, 245, p. 582, "Models of Elliptical Galaxies:NGC 3379, 4261, 4278 and 4472"

Wade, R.A., et al. 1991, IAU CoUoq. 122, ed A. CassateUa, R. Viotti (Berlin, Springer-Verlag), p. 195,"An Ha Image of Nova VI500 Cygni Twelve Years After Outburst"

Wagner, R.M., et al. 1990, Accretion-Powered Compact Binaries, ed. C.W. Mauche (Cambridge U. Press),p. 29, "Optical Observations of the X-Ray Nova V404 Cygni"

Wallace, L., Livingston, W. 1990, J Geophys. Res., 95D, p. 16, 383, "Spectroscopic Observations ofAtmospheric Trace Gases Over Kitt Peak 2. Nitrous Oxide and Carbon Monoxide From 1979 to 1985"

Waller, W.H. 1990, The IntersteUar Medium in External Galaxies: Summaries of Contributed Papers,ed. D.J. HoUenbach, H.A. Thronson, Jr. (NASA), p. 334, "Starburst Outflows from Nearby Galaxies"

Waller, W.H. 1990, PASP, 102, p. 1217, "Emission-Line and Continuum Fluxes from Narrow-and Broad-Band Imagery"

Waller, W.H. 1991, ApJ, 370, p. 144, "Relics of an Emptive Starburst in NGC 1569"

Walter, F.M., Skinner, S.L., Boyd, W.T. 1990, PASP, 102, p. 754, "BD +24°676: An Intermediate-Mass,Pre-Main-Sequence Star"

Warren, S.J., et al. 1991, ApJS, 76, p. 1, "A Wide-Field Multicolor Survey for High-Redshift Quasars,z > 2.2. I. Photometric Catalog and Survey Selection Function"

19

Warren, S.J., Hewett, P.C, Osmer, P.S. 1991, ApJS, 76, p. 23, "A Wide-Field Multicolor Survey for High-Redshift Quasars, z > 2.2 II. The Quasar Catalog"

Webb, J.R., et al. 1990, AJ, 100, p. 1452, "The 1987-1990 Optical Outburst of the OW Quasar 3C 279"

Wegner, G., et al. 1991, ASP Conference 15, ed. D.W. Latham, L.A. Nicolaci da Costa (ASP), p. 129,"On Determining the DR - logo Relation for EUiptical Galaxies Using Red CCD Images"

WeidenschiUing, S.J., et al. 1990, Icarus, 86, p. 402, "Photometric Geodesy of Main-Belt Asteroids.III. Additional Lightcurves"

Weis, E.W. 1991, AJ, 101, p. 1882, "VRI Photometry of Late Dwarf Common Proper Motion Pairs"

Werner, M.W., et al. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 208, "Two Micron ImagingPolarimetry of the Galactic Center Region"

Westphal, J.A., et al. 1991, ApJ, 369, p. L51, "Hubble Space Telescope Wide-Field/Planetary CameraImages of Saturn"

Whitmore, B.C., et al. 1990, AJ, 100, p. 1489, "New Observations and a Photographic Adas of Polar-RingGalaxies"

Wilson, A.S., Nath, B. 1990, ApJS, 74, p. 731, "A Survey of the Profiles of Narrow Emission Lines inSeyfert Galaxies"

Winget, D.E., et al. 1990, ApJ, 357, p. 630, "Whole Earth Telescope Observations of the White DwarfG29-38: Phase Variations of the 615 Second Period"

Winkler, P.F., Olinger, T.M., Ratcliff, S.J. 1990, CCDs in Astronomy. II., ed. A.G.D. Philip, D.S. Hayes,S.J. Adelman (Schenectady, NY, Davis Press), p. 55, "Wide Field Images of Galactic SupemovaRemnants"

Winkler, P.F., Roberts, P.F., Kirshner, R.P. 1991, Supernovae, ed. S.E. Woosley (Berlin, Springer-Verlag),p. 652, "Spectrophotometry of Cas A: Implications for Nucleosynthesis in Massive Stars"

Wolff, S.C. 1990, AJ, 100, p. 1994, "Luminosities, Masses, and Ages of B-Type Stars"

Woodward, C.E., et al. 1990, ApJ, 365, p. 252, "Infrared Imaging of the M8 Hourglass"

Wyckoff, S., Tegler, S.C, Engel, L. 1991, ApJ, 368, p. 279, "Ammonia Abundances in Four Comets"

Wyckoff, S., Tegler, S.C, Engel, L. 1991, ApJ, 367, p. 641, "Nitrogen Abundance in Comet HaUey"

Yamashita, T., et al. 1991, ApJ, 373, p. 560, "The Dense, Inner Part of the Protostellar Disk: ProtostarCandidates in GGD 27 IRS"

20

Zeilik, M., et al. 1990, ApJ, 363, p. 647, "Long-Term Starspot Activity of Short-Period RS CanumVenaticorum Stars. IV. WY Cancri"

Zheng, W., Grandi, S.A. 1990, IAU CoUoq. 124, ed. J.W. Sulentic, W.C. Keel, CM. Telesco (NASA),p. 251, "Interacting Nuclei in Distant Galaxies"

Zickgraf, F-J., et al. 1990, PASP, 102, p. 925, "CCD Photometric UBVR Sequences for NGC 2403 andM 81"

Zinnecker, H., et al. 1991, ASP Conference 14, ed. R. Elston (ASP), p. 270, "First 2-D Infrared SpeckleObservations of Pre-Main Sequence Binaries"

21

APPENDIX D

National Solar ObservatoryJuly 1990 to June 1991 Publications List

During the period 1 July 1990 through 30 June 1991, a total of 123 visiting scientists used the telescopeson NSO/Kitt Peak and NSO/Sacramento Peak. A total of 154 publications were written by visitors andstaff.

Abrams, M.C, et al. 1990, ApJ, 363, p.326, "Highly Excited Rotational States of the Meinel Systemof OH"

Altrock, R.C. 1990, NASA CP 3086, ed. K.H. Schatten, A. Arking (Goddard Space Flight Center), p.287,"The Variation of Solar Fe XIV and Fe X Flux Over 1.5 Solar Activity Cycles"

Altrock, R.C, et al. 1991, Solar-Geophysical Data, Part 1, 547-548, ed. H.E. Coffey (Boulder, CO,NO AA), "Sacramento Peak Coronal Synoptic Maps, 1990"

Altrock, R.C, et al. 1991, Solar-Geophysical Data, Part 1, 547-548, ed. H.E. Coffey (Boulder, CO,NOAA), "Coronal Line Emission (Sacramento Peak), 1990"

Anderson, E.R., Duvall, T.L., Jefferies, S.M. 1990, ApJ, 364, p.699, "ModeUng of Solar Oscillation PowerSpectra"

Antonucci, E. 1990, ApJ, 360, p.296, "Rotation of the Photospheric Magnetic Fields: A North-SouthAsymmetry"

Ayres, T.R., Brault, J.W. 1990, ApJ, 363, p.705, "Fourier Transform Spectrometer Observations of SolarCarbon Monoxide. III. Time-Resolved Spectroscopy of the Av=l Bands"

Bernath, P.F., et al. 1991, J. Molec. Spectrosc. 147, p.16, "Spectroscopy of the CH Free Radical"

Bonaccini, D., et al. 1991, National Solar Observatory/Sacramento Peak Workshop Series 11,ed. L.J. November (Sunspot, NSO), p.251, "Small Scale Magnetic Field Mapping with High TemporalResolution"

Braun. D.C., DuvaU, T.L. 1990, Sol. Phys., 129, p.83, "p-Mode Absorption in the Giant Active Regionof 10 March 1989"

Braun. D.C., Duvall, T.L., Jefferies, S.M. 1990, Proceedings of Oji International Seminar, ed. Y. Osaki,H. Shibahashi (Springer-Verlag), p.181, "Observations of p-Mode Absorption in Active Regions"

Bruning, D.H., Saar, S.H. 1990, Sixth Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun,ed. G. WaUerstein (San Francisco, ASP), p.165, "Rotational Enhancement of Line Asymmetries in F9-G2Dwarfs"

Bumba, V. 1991, BuU. Astron. Inst. Czechoslovakia, 38, p.92, "Search for Giant Elements of Convectionwith the Aid of Magnetic Tracers"

Canfield, R.C, et al. 1990, ApJ, 363, p.318, "H-alpha Spectra of Dynamic Chromospheric Processes inFive WeU-Observed X-Ray Flares"

Cannon, A.T., Marquette, W.H. 1991, Sol. Phys., 131, p.69, "The Evolution and Orientation of EarlyCycle 22 Active Regions"

Cauzzi, G., Smaldone, L.A. 1990, SPIE, 1318, ed. B. McNamara, J.M. Lemer, "Bi-dimensional Solar

Spectroscopy with the 20 mA Filter: CapabiUties and Constraints"

Chidester, S.D., Harvey, J.W., Hubbard, R.P. 1991, Appl. Opt., 30, p.12, "Measurement of CrystalRetarders"

Chou, D.Y., et al. 1991, ApJ, 372, p.314, "Power Spectra of Solar Convection"

Coffey, H.E., Wilkinson, D.C 1991, MAX '91, Workshop 3, ed. R.M. Winglee, A.L. Kiplinger, p.267,"Some Comparisons of the Forbush Decrease Periods of 24-25 April 1984 and 13-14 March 1989"

Dara, H.C, Alissandrakis, C.E., Koutchmy, S. 1991, National Solar Observatory/Sacramento PeakWorkshop Series 11, ed. L.J. November (Sunspot, NSO), p.257, "SmaU Scale Magnetic Field Mappingwith High Temporal Resolution"

Darvann, T.A., Koutchmy, S., Zirker, J.B. 1990, IAU CoUoquium 117, ed. E. Tandberg-Hanssen,V. Ruzdjak, "An Automated Procedure for Measurement of Prominence Transverse Velocities"

Davis, S.P., et al. 1991, J. Opt. Soc. Am., 8, p.198, "CN Vibration-Rotation Spectrum"

Deming, D., et al. 1990, ApJ, 364, p.L49, "Observations of the 12.3 Micron Mg I Emission Line Duringa Major Solar Flare"

Deming, D., et al. 1991, National Solar Observatory/Sacramento Peak Workshop Series 11,ed. L.J. November (Sunspot, NSO), p.341, "Polarimetry in the Infrared"

Dere, K.P. 1991, Adv. Space Res. 11, 5, p.191, "High Resolution Solar Physics from Rockets"

Dere, K.P., Bartoe, J.D., Brueckner, G.E. 1991, J. Geophys. Res., 96, p.9399, "Explosive Events andMagnetic Reconnection in the Solar Atmosphere"

Deubner, F.L., et al. 1990, A&A, 236, p.509, "Dynamics of the Solar Atmosphere. IV. Evanescent Wavesof Small Amplitude"

Dobson, A.K., et al. 1990, Sixth Cambridge Workshop on Cool Stars, SteUar Systems, and the Sun,ed. G. WaUerstein (San Francisco, ASP), p.132, "Variance Components in Ca II H + K Time-SeriesObservations"

Donnelly, R.F., Puga, L.C 1990, Sol. Phys., 130, p.369, "Thirteen-Day Periodicity and the Center-to-LimbDependence of UV, EUV, and X-Ray Emission of Solar Activity"

Dunn, R.B., Darvann, T.A. 1990, Turbulence Power Spectral Density, "Using the Sun to Smdy the Earth'sAtmosphere"

Dunn, R.B. 1991, SPIE, 1271, p.216, "NSO/SP Adaptive Optics Program"

Dunn, R.B., Smartt, R.N. 1991, Adv. Space Res. 11,5, p.139, "High Resolution Telescopes at the NationalSolar Observatory"

DuvaU, T.L., et al. 1990, ApJ, 373, p.308, "Measurements of High Frequency Solar Oscillation Modes"

Falciani, R., et al. eds. 1991, Adv. Space Res. 11, 5, "Opening Frontiers in Solar Research"

Fernando, W.T., Bernath, P.F. 1991, J. Molec. Spectrosc. 145, p.392, "Fourier Transform Spectroscopyof the A1 II - X!X+ Transition of BH and BD"

Fernando, W.T., O'Brien, L.C, Bernath, P.F. 1991, J. Chem. Phys., 93, p.8482, "Fourier TransformEmission Spectroscopy: The B4" I - X4T Transition of BC"

Flaud, J.M., et al. 1990, Appl. Opt., 29, p.3667, "Improved Line Parameters for Ozone Bands in the10 u.m Spectral Region"

Flaud, J.M., et al. 1990, (Academic Press), p.599, "Adas of Ozone Spectral Parameters from Microwaveto Medium Infrared"

Foing, B.H., Catala, C, and the MUSICOS Team 1990, Proceedings of Oji International Seminar, ed. Y.Osaki, H. Shibahashi (Springer-Verlag), p.457, "MUSICOS Network for Multi-Site ContinuousSpectroscopy"

Foukal, P. 1990, Phil. Trans. Roy. Soc. London, 330, p.591, "Solar Luminosity Variations OverTimescales of Days to the Past Few Solar Cycles"

Fmm, C.I., Engleman, R., Bernath, P.F. 1990, J. Chem. Phys., 93, p.5457, "Fourier Transform EmissionSpectroscopy at 13 um: Vibration-Rotation Spectrum of SiS"

Fmm, C.I., et al. 1991, Chem. Phys. Lett., 176, p.504, "The Infrared Emission Spectrum of Gas Phase C60(buckminsterfuUerene)"

Gaizauskas, V., Harvey, K.L. 1991, Flares 22 Workshop, ed. B. Schmieder, E. Priest, p.25, "CollisionsBetween Nested Sunspots: A Pathway to Flares"

Gucnther, E., Mattig, W. 1991, A&A, 243, p.244, "High Resolution Line Profiles in Quiet and PlageRegions of the Sun"

Gunson, M.R., et al. 1990, J. Geophys. Res., 95, p.13867, "Measurements of CH4, N2, CO, H:0, and 03in the Middle Atmosphere by the ATMOS Experiment on Spacelab 3"

Haber, D.A., HuT, F. 1990, Challenges to Theories of the Stmcmre of Moderate Mass Stars, ed. D. Gough,J. Toomre (Springer-Verlag;. "Simulation of the Effect of Active Regions on Intermediate-Degree SolarOscillations"

Haber, D.A., HiU, F., Toomre, J. 1990, ChaUenges to Theories of the Structure of Moderate Mass Stars,ed. D. Gough, J. Toomre (Springer-Verlag), "Effects of Spatial Filtering on High-1 Power Spectra andRotational Splitting Inversions"

Haber, D.A., Hill, F., Toomre, J. 1990, ChaUenges to Theories of the Stmcmre of Moderate Mass Stars,ed. D. Gough, J. Toomre (Springer-Verlag), "The Role of f-Modes in the Inversions of High-1 RotationalSplittings"

Harvey, J.W. 1990, Proceedings of Oji International Seminar, ed. Y. Osaki, H. Shibahashi(Springer-Verlag), p.l 15, "Trends in HeUoseismology Observation and Data Reduction"

Hill, F. 1990, Sol. Phys., 128, p.321, "A Map of the Horizontal Rows in the Solar Convection Zone"

Hill, F. 1990, Proceedings of Oji International Seminar, ed. Y. Osaki, H. Shibahashi (Springer-Verlag),p. 173, "The Effect of Large-Scale Flows on OsciUation Ring Diagrams"

Hill, F., et al. 1991, ApJ, 369, p.237, "Simulation of Effects of Atmospheric Seeing on the Observationof High-Degree Solar OsciUations"

Hill, F.. Leibacher, J.W. 1991, Adv. Space Res. 11,4, p.149, "Ground-Based HeUoseismology Networks"

Hill, F., et al. 1990, Challenges to Theories of the Structure of Moderate Mass Stars, ed. D. Gough,J. Toomre (Springer-Verlag), "Solar OsciUation Ring Diagrams from Mt. Wilson Full-DiskMagneto-Optical Dopplergrams"

Howard, R.F., Harvey, J.W., Forgach, S. 1990, Sol. Phys., 130, p.295, "Solar Surface Velocity FieldsDetermined from SmaU Magnetic Features"

Howard, R.F., et al. 1990, IAU Symposium 142, ed. V. Krishan, E. Priest (Kluwer), p.107, "SunspotMotions from a Study of Kodaikanal and Mount WUson Observations"

Howard, R.F. 1991, Sol. Phys., 131, p.239, "The Magnetic Fields of Active Regions. IN. Growth andDecay of Magnetic Flux"

Howard, R.F. 1991, Sol. Phys., 131, p.259, "The Magnetic Fields of Active Regions. IV. MeridionalMotions"

Howard, R.F. 1991, Sol. Phys., 132, p.49, "The Magnetic Fields of Active Regions. V. Magnetic AxisOrientations"

Howard, R.F. 1991, Sol. Phys., 132, p.257, "The Magnetic Fields of Active Regions. VI. Magnetic AxisTilt Changes"

Jackson, B., Gold, R., Altrock, R.C. 1991, Adv. Space Res. 11, 1, p.377, "The Solar Mass Ejection

stkeT^fdes"11^"' DL- 1991> APJ' 3?2' P'694' "°n *e InfercnCe °f Magnet,C FieId Ve«™ f™

ifiriiCV'T" ^f DL- JSS; Nati°nal S°lar 0bse^ato^Sacramento Peak Workshop Series 11Profi.es" P°t' }> P-373' "°ireCt InferenCe °f MagnetiC Fidd Vector* 'om StokesJefferies, S.M., et al. 1990, Proceedings of Oji International Seminar, ed. Y Osaki H Shibahashi(Spnnger-Verlag), p. 135, "HeUoseismology from South Pole: Results from the 1987 Campaign"

Jefferies S.M, DuvaU, T.L. 1991, Sol. Phys., 132, p.215, "A Simple Method for Correcting SpatiallyResolved Solar Intensity OsciUation Observations for Variations in Scattered Light" *

Jensen, E. 1990, IAU CoUoquium 117, ed. E. Tandberg-Hanssen, V. Ruzdjak (Springer-Verlag) p129Support of Quiescent Prominences" 8 p '

Keller C.U., et al. 1990 A&A, 233, p.583, "Stmcmre of Solar Magnetic Fluxtubes from the Inversionof Stokes Spectra at Disk Center"

Keller C.U et al. 1990, A&A, 236, p.250, "Solar Magnetic Field Strength Determinations from HighSpatial Resolution Filtergrams" &

KeUer, C.U 1991, National Solar Observatory/Sacramento Peak Workshop Series 11, ed. LJ November(Sunspot, NSO), p. 124, "High Spatial Resolution Polarimetry Using Filtergrams"

Mercury '̂' *""' ^ ^^ T'H" l"h ^^ 252' P'4?4' "Detemination of Potassium on

Kn°,r^" ^fg" Wu NCSiS' A- 199°' A&A' 239' P-340' ',The Hei§ht ^Pendence of Intensity Structuresin the Solar Photosphere

Ph0oTo^PhRereMattig' W" NCSiS' A' 1991' A&A" 243' ?25h "^ SmaU"Scale Velocity FieJd in the SolarKoutchmy, S et al. 1990, SPIE, 1235, p.849, "Real-Time Image Processing and Data Handling forGround-Based and Spacebome Coronal Observations"

Koutchmy S., Zirker, J.B., Darvann, T.A. 1990, IAU CoUoquium 117, ed. E. Tandberg-Hanssen, VPro™nenc!'Pnnger g)' "DiStribUti°n °f Velocities ir> the Pre-Emptive Phase of a Quiescent

Koutchmy, S., et al. 1990, National Solar Observatory/Sacramento Peak Workshop Series 11ed. L.J. November (Sunspot, NSO), p.263, "High Spatial Resolution V: Stokes Polarimetry to Measurethe Zeeman Effect in Flux Tubes and Prominence Filament Threads"

Koutchmy, O. 1991, Flares 22 Workshop, ed. B. Schmieder, E. Priest, p. 103, "The Magnetic FieldConfiguration and Motions Over Regions with Impulsive Events and Prominence-Thread-Feet"

Koutchmy, S. 1991, National Solar Observatory/Sacramento Peak Workshop Series ll.ed. L.J. November(Sunspot, NSO), p.237, "High Spatial Resolution Observations of Magnetic Flux Elements"

Kumar, P., et al. 1990, Proceedings of Oji International Seminar, ed. Y. Osaki, H. Shibahashi(Springer-Verlag), p.87, "What are the Observed High-Frequency Solar Acoustic Modes?"

Kundu, M.R., Gopalswamy, N. 1990, Sol. Phys., 129, p.133, "Filament Eruption and Storm Radiation atMeter-Decameter Wavelengths"

Kundu, M.R., et al. 1990, NSF ATM88-16008, "A CoUection of Images of the Solar Corona at MeterWavelengths, in White Light, the 10830 He Line, and Extrapolated Magnetic Fields"

Lang, K.R. 1991, Adv. Space Res. 11, 1, p.59, "VLA Observations of the Inner Corona"

Lantos, P., et al. 1990, Solar-Terrestrial Predictions Workshop, ed. R.J. Thompson et al. (NOAA), p.l,"Leura Solar-Terrestrial Prediction Workshop Working Group Report"

Lin, J., et al. 1990, Acta Astron. Sinica, 31, p.313, "The Morphology Evolution of the Cool Post-FlareLoop System of April 28, 1980"

Lites, B.W., et al. 1991, National Solar Observatory/Sacramento Peak Workshop Series 11,ed. L.J. November (Sunspot, NSO), p.3, "Preliminary Results from the HAO/NSO Advanced StokesPolarimeter Prototype Observing Run"

Livingston, W.C, Talent, D. 1990, S&T, 80, p.319, "Stalking Geosats with a Camera"

Livingston, W.C. 1990, Cimate Impact of Solar Variability, NASA CP 3086, ed. K. Schatten, A. Arking(Goddard Space Flight Center), p.336, "Secular Change in Equivalent Width of C5380 1978-90"

Livingston, W.C. 1991, J. of CUmate Change, 18, p.121, "Energy Input to the Earth"

Livingston, W.C. 1991, IAU CoUoquium 130, ed. I. Tuominen, p.246, "Convective Signature of the SolarCycle from FTS Sun-as-a-Star Line Asymmetry Changes"

Livingston, W.C. 1991, National Solar Observatory/Sacramento Peak Workshop Series 11,ed. L.J. November (Sunspot, NSO), p.356, "Sampling V-Stokes on the Solar Disk with Fe I 15648 A andH Paschen (3"

Livingston, W.C. 1991, Nature, 350, p.45, "Radial Filamentary Stmcmre in a Sunspot Umbra"

Malathy Devi, V., et al. 1990, J. Molec. Spectrosc, 143, p.381, "Line Positions and Intensities for the y2+ 3y3 Band of 1603 around 2.7 um"

Mauas, P.J. 1990, ApJS.74, p.609, "The White-Light Rare of 1982 June 15: Observations"

Mitchell, W.E., Livingston, W.C. 1991, ApJ, 372, p.336, "Line-Blanketing Variations in the IrradianceSpectrum of the Sun from Maximum to Minimum of the Solar Cycle"

Moran, T., Foukal, P. 1991, AFGL Technical Report 90-0192, "An Electrograph for the Measurement ofSolar Plasma Electric Fields"

Moran, T., Foukal, P. 1991, National Solar Observatory/Sacramento Peak Workshop Series 11,ed. L.J. November (Sunspot, NSO), p.393, "Measurement of Polarization-Dependent Stark Broadening asa Diagnostic of Electric Fields in the Solar Atmosphere"

MuUer, R., et al. 1990, Publications of Debrecen Heliophysical Observatory, 7, p.44, "Structure andEvolution of the Large Scale Granulation Flow Pattern"

MuUer, R., et al. 1990, Publications of Debrecen Heliophysical Observatory, 7, p.150, "Formation ofNetwork Bright Points by Granule Compression"

Nash, A.G. 1991, ApJ, 366, p.592, "Rotation of the Sun's Outer White-Light Corona Determined fromSolwind Data"

Nash, A.G. 1991, Adv. Space Res. 11, 1, p.47, "Coronal Rotation at 3.5 Solar Radii Determined fromSolwind Data"

Neff, J.E. 1991, Proceedings of Second MUSICOS Workshop, p.35, "Surface Structures and Hares on RSCVn-Type Stars"

Neidig, D.F. 1990, Solar-Terrestrial Predictions, Leura, Australia, ed. R. Thompson et al. (NOAA), p.154,"Solar Flare Forecasting: Progress and Future"

Neidig, D.F., Wiborg, P.H., Seagraves, P.H. 1990, Solar-Terrestrial Predictions, Leura, Australia, ed. R.Thompson et al. (NOAA), p.541, "The Role of Persistence in the 24-Hour Flare Forecast"

Nitta, N., et al. 1991, ApJ, 374, p.374, "Coronal Magnetic Structures Observing Campaign.I. SimultaneousMicrowave and Soft X-ray Observations of Active Regions at the Solar Limb"

November, L.J. 1991, National Solar Observatory/Sacramento Peak Workshop Series 11,ed. L.J. November (Sunspot, NSO), p.149, "Using the Zeeman Spectral-Polarization Symmetry forTelescope Calibration"

November, L.J., ed. 1991, Solar Polarimetry, National Solar Observatory, Sunspot, New Mexico.

O'Brian, T.R., et al. 1991, J. Opt. Soc. Am., 8, p.l 185, "Lifetimes, Transition Probabilities, and LevelEnergies in Fe I"

Pap, J., et al. 1990, NASA CP 3086, ed. K.H. Schatten, A. Arking (Goddard Space Flight Center), p.189,"Modeling Solar Lyman Alpha Irradiance"

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