the echelle user manual

7/30/2019 The echelle user manual

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Echelle User Manual

H. Navasardyan, E. Giro, A. Siviero, P. Marrese, D. Fantinel, V. Chiomento, L. Traverso,L.Lessio, L. Contri, A. Frigo

Jan. 2006

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Contents

Introduction..............................................................................................................................3Optical Layout..........................................................................................................................3Gratings...................................................................................................................................4Echelle Filters.......................................................................................................................... 4

.............................................................................................................................................5Echelle Slits ............................................................................................................................ 5Slit and Decker viewer ............................................................................................................6Echelle Detector.......................................................................................................................7Bias and Dark currents ............................................................................................................8Comparison Lamp....................................................................................................................9Instrument Focus.....................................................................................................................9Telescope Focus.......................................................................................................................9Echelle Graphic User Interface ............................................................................................... 9

Starting and initializing the system................................................................................... 10CCD Initialization..............................................................................................................11

Init Rotation....................................................................................................................... 11Stopping the System...........................................................................................................12Subwindows.......................................................................................................................12

header fits ......................................................................................................................12Telescope ..................................................................................................................... 14Exposure ....................................................................................................................... 15Command line ...............................................................................................................15Rotation .........................................................................................................................16Autoguider .................................................................................................................... 16

Quick look analysis .......................................................................................................... 17Set-up Request....................................................................................................................... 18

Night report............................................................................................................................ 19Troubleshooting .................................................................................................................... 19Reference............................................................................................................................... 19Appendix ...............................................................................................................................20Echelle Orders in Different Cross-Disperser Angels............................................................. 22Th-Ar Atlas............................................................................................................................ 60

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Gratings

The echelle grating has 79 ln/mm, blaze angle 63.433 degrees and ruledarea of 128x254 mm.

The parameters for available three crossdisperser gratings are presented in Table 1.The changing of cross disperser should be doneby the staff technicians during the daytime.

The echelle orders with different angle ofall cross dispersers are presented in Appendix.

The angle position of cross disperser ispossible to change by the micrometer screwsshown in the Figure 2.

Figure 2. The screws for changing CrossDisperser angle

Table 1. Gratingsgrating type

ln/mmBlaze

()Dispersion

(/mm)Spectral Purity

()79 (echelle R2) 4990 7.3 0.2

CD150 8000 327 4.9CD300 4980 163 2.5CD1200 5977 39 0.6

Echelle Filters

Two second-order suppressing Echelle filters (OG455, OG515) areavailable. The transmission curves of the filters are shown in figure 3.

In order to insert a filter it is necessary to move filter bar (see Figure A1).The position V means NO FILTER. Positions 1 and 2 are OG455 and OG515 filters

respectively.

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Figure 3. Transmission curves of echelle filters

Echelle Slits

The slit, placed at the focal plane of the telescope, is 30 mm long (380arcsec) and its aperture ranges between 50 m and 2.5 mm (0.65-31.5 arcsec)with 50 m steps set by a micrometer. The slit size is possible to change by themicrometer screw shown on figure A1.

The slit length can be changed moving the decker (see Figure 4) up anddown.

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Figure 4.Decker

Slit and Decker viewer

A Proxitronic tv intensified camera displays the telescope field-of-view

superimposed on the slit, with a size of 2.3x2.2 arcmin. The measured limitingmagnitude is approximately 16.2. The camera parameters (gain, offset andelectronic shutter exposure time) can be adjusted using the instrument software,which is installed on PCControlRoom. For executing the software double-click onProxitronic icon on the desktop end enter with the COM2. The main windowcalled DCU (see Figure 5) becomes red when the camera is off and green when ison. Clicking on the buttons of DCU it is possible to open the necessary parametercontrol window. In Figure 5 are shown mostly used windows.

Every time when the camera is switched on the software starts with the

highest CCD integration time (1/50 sec), which can damage the CCD in the caseof available strong light. So, it is strongly recommended to switch-off alllamps in the dome (including calibration lamp) before switching on the

camera. Then, after minimizing CCD counts (e.g. putting 1/1000 sec) it ispossible to turn on needed light or to point a bright object.

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Figure 5. Proxitronic software windows

Echelle Detector

The current detector of Echelle has been mounted on June 2004. It is E2VCCD47-10 AIMO back illuminated CCD Imager, with 1100 x 1100 13m pixels,

which corresponds to 0.41 arcsec/pxl for cross disperser CD1200, 0.54 arcsec/pxlfor CD300 and 0.57 arcsec/pxl for CD150 on the Echelle focal plane. These areaverage values and can be slightly different depending on used angle of crossdisperser.

The architecture of the CCD controller follows the TNG standards (Bonannoet al.~2000) .

Typical readout time is about 40 seconds for the full frame. It is possible toselect a window on the chip to reduce readout time. Binning the pixels is notcurrently available.

There are two different CCD amplifiers therefore two readout modes. Thecharacteristics corresponding to different readout modes are presented in table 2.

The readout mode by default is - Readout Mode 2.To exclude the overscan region, the images can be trimmed (X axis: pixel 9to 1064; Y axis: pixel 1 to 1032). The CCD suffers from fringing in the red .

CCD characteristics are reported in Table 1 and its quantum efficiency inFigure 6.

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Table 2. CCD Characteristics

Parameter ValueReadout Mode 1 Readout Mode 2

Format 1100 X 1100 pxl

Pixel size 13mPixel scale on echelle

CD150CD300CD1200

0.57 /pxl0.54 /pxl0.41 /pxl

Readout noise 9.1 e- 8.5 e-

Gain 2.33 e-/ADU 1.17 e-/ADUDark current 2 ADU/hour 3 ADU/hourDynamic range 50 000Fringing 17% at 8000

Figure 6. The red dashed curve is Quantum efficiency of Echelle CCD

Bias and Dark currents

The bias level is about -31 780 and the stability during the night is within 6ADU. The measured dark current is less than 5e-/pixel/hour.Currently no badpixel visible.

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Comparison Lamp

A Th-Ar lamp serves as the comparison source for the Echelle spectrographwhich provides a good calibration exposure for the total spectral range. Thepower supply of the lamp should be turned on only when the proxitronic camerais switched off and the calibration arm is being inserted. Typical exposure time isnear to 15 seconds, which varies a little bit depending on the used crossdisperser and orders. It is much higher for CD1200 and can reach to 60sec inblue orders.

Instrument Focus

Spectrograph focus remains an entirely manual adjustment. Initial focusingof the spectrograph is normally done by the staff. Nevertheless, changes of thesetup and big variation off temperature cause for redetermining the focus setting.The basic steps of this procedure are described in this section.

Focusing consists of taking a series of ThAr exposures, moving thecollimator for each exposure, and analyzing the frames with the atv(Echelle GUI

/ Utilities). The collimator position is controlled with a micrometer screw, andmotion steps of 0.5-mm give the best results.

A satisfactory criterion for the focus quality is a fwhmof about 2.7 3.5pixels for the images taken with the slit 100m.

Measured best focus on 23 Aug. 2004 for the temperature 18.2 C was 8mmwith CD 300 ln/mm and slit 100m.

Telescope Focus

Focusing of the telescope is performed by moving the secondary mirroralong Z axis. The determination of the best focus can be done by comparison ofseveral spectra of point sources obtained at different focus positions.

Echelle Graphic User Interface

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The Ekar Echelle Graphic User Interface (EGUI) allows the observer toperform the operations necessary to manage the echelle spectrograph, therotator and CCD during a typical observational session with already mountedsetup.

The main window (see figure 7) is composed of six different subwindowseasy to identify and few menus (FILE , SETUP, UTILITIES, HELP) on upper panel.

Figure7. EGUI Main window

Starting and initializing the system

In order to start up the system , it is necessary:

switch on the electric power of the continuity group at the pedestal of thetelescope;

switch on the VME rack and wait until the boot is terminated; login with remoto account on wusche ; initializelightbus182 andtelescope interfaceon PC Coordinate click on Echelle-Start for executing EGUI (UNIX menu bar over the

clock);

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Initialize CCD and rotation .

CCD Initialization

For initializing the CCD select Init CCD from Setup menu. A dialog boxpops up (see Fig. 8) just before the initialization file is executed asking to confirmthe loading of the default CCD configuration. By default the CCD configurationloaded corresponds to amplifier readout without binning. Using the CCD binningfrom pull-down menu is then possible to select the binning (currently binning isnot active).

The Boot button performs several functions. First of all, it starts thecommunications between the transputer on the CCD controller and the transputeron the VME. Then it executes an initialization file that loads the CCD biases andclocks, actually making the CCD operating.

The Quitis used to close Init CCD window.

Figure 8.CCD initialization windows

Init Rotation

For initializing the rotation first visually check if the instrument is free forrotation, switch on the telescope then select init rotation from Setup menu.Click INIT ROTATION button (see Figure 9) for initializing the rotation orQUIT for exiting.

When VME and EGUI remain switched on during the day while thetelescope was switched off the rotation must be reinitialized.

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Figure 9.Rotation initialization windows

Stopping the System

To stop the system press exitat the File menu of EGUI main windowand

wait until the window is closed, then you can switch off the VME , CCD androtation controllers.

Figure 10.Header fits subwindow

Subwindows

header fits

This subwindow allows the user to insert the some keyword parameters ofthe fits image and save it. These parameters are :

1. Image Type

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current has to be obtained. These exposure are taken keeping the CCD shutterclosed. All the lamps should be switched off before starting dark exposure.

o Science

The science exposure type is selected whenever the spectra of an astronomical

object has to be taken

o Wipe

The wipe exposure type should be selected for CCD wiping.

2. the name of object;

3. the name of observer ;

4. comment line (it can be any important comment concerning to theobtained image, which can be useful during data reduction );

5. the number of fits image; this field automatically will show theimage number given by UIF. This field is not editable;

6. Save button; normally the images transferred from VME arewritten in the scratch directory of workstation wusche. With thesave button it is possible to save them in the archive. Not savedimages arent lost, it possible to recover them . Before saving it ispossible to change all variables in header fits subsection.

7. slit size;

8. filter name, if it is inserted;

9. cross disperser inserted;

10. cross disperser angle;

Telescope

This subwindow shows the current telescope position (RA and DEC)with epoch and the parallactic angle corresponding to the current position(parallactic angle is not yet working). In this subwindow the parametersare not editable.

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Figure11. Telescope subwindow.

Exposure

This subwindow consists of five editable fields called Exp. time, left,right, down and up respectively, three buttons and track-bar.

Exp. time is the field where observer should to insert exposure time in seconds.Left, right, down, up are fields for definition of CCD subareas (boxes) in order

to decrease readout time of CCD. The box size in both direction should not be oddnumber.

Track-bar shows already integrated time in seconds.Startbutton is used to start an exposure.Stop terminates the exposure , reading the CCD and saving the data acquired up

to that moment to the disk.Pause allows to pause an ongoing exposure. The exposure time is stopped, the

CCD shutter is closed but the CCD remains in integration. The exposure can berestarted using the resume button.

Resume allows to resume an exposure previously paused. This button appearsonly when thepause button is pushed.

Figure 12.Exposure subwindow

After each exposure the image is automatically displayed with atvprogram (see Figure 16).

Command line

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In this subwindow it is possible to execute in a command line all the lowlevel operations described above. When command line is used the exposurewindow is inactive. Anyway it is strongly recommended to avoid to use thissubwindow, if the user has not an engineering knowledge of the system.

Figure 13. Command line subwindow

Rotation

It is possible to take a spectra of an object at the desired position angleusing Rotation subwindow. For this it is necessary:

1. Initialize the rotation, if it is not initialized yet2. Insert desired angle (expressed in degrees from north to east) into go

to field and press Go To button.

Stop button is for aborting the rotation.The rotation range is [-90; 90]. The rotation angle 0.0 corresponds slit

position east-west.

Figure 14. Rotation subwindow

Autoguider

This subwindow allows the user to start and stop auto-guider. For usingautoguider follow these steps:

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1. Press Grab button and wait till the image from the monitor ofProxitronic Camera will be transferred and displayed on the

Autoguider subwindow.2. Using the left mouse button click on the position of the chosen star,

which can be any field star available or the object itself. A box willappear at the star position. Use left mouse button to move, centralbutton to resize the box and right one to confirm the box. After

confirmation a box will appear on the monitor of Proxitronic Camera.The procedure can be iterated if the box is not satisfactory.

3. choose Guide star, if you want to start auto-guiding moving thecenter of box on the star or Guide box, if you want to start auto-guiding moving the star to the center of the box.

4. Use Guide off for stopping the auto-guider.

It is possible to start immediately auto-guiding pressing only on Guide-boxbutton, if the star is inside previously selected box.

Figure15. The guide subwindow

Quick look analysis

Preliminary Examination of images is possible to do by ATV (Aaron'sinteractive front end for idl TV ) program, which pops up automatically after each

exposure (see Fig.16). It is possible also to open it from EGUI Utilites menu.Atv allows complete interactive control of the image scaling, color table,color stretch, and zoom and to check counts moving the cursor. It handlesimage blinking, and overplotting of text, line graphics. It also does point-and-click aperture photometry, and can produce publication-quality postscript output.

Detailed instruction for using the program is possible to find pressing Helpon upper panel ofatvwindow or visiting the web site:

http://www.physics.uci.edu/~barth/atv/instructions.html.

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Night report

At the end of night the observer astronomer is required to fill Observer's Night ReportForm at Asiago Observatory:

http://www.pd.astro.it/asiago/2000/2600.html

When the night report is submitted an e-mail report will be sent to the instrument staff.

Troubleshooting

Init rotation

An error message appears is not connected, even if the telescope is switched on.

Close the error message window and try to repeat the initialization.

Auto-guiding

Grab button is not active

Exit from EGUI and reopen it. Dont forget to initialize the system again.

Reference

Bonanno, G.; Bruno, P.; Cosentino, R.; Scuderi, S.; Bortoletto, F.; D'Alessandro, M.; et al. ,2000, Optical Detectors for Astronomy conf. proceedings, 389Desidera, S.; Fantinel, D.; Giro, E.; Navasardyan, H. , 2005 , AFOSC manualMunari, Ulisse; Lattanzi, Mario G., 1992, PASP, 104, 124

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Appendix

Figure A1, 2. Echelle instrument ; PS= Power Supply

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Echelle Orders in Different Cross-Disperser Angels

Here we present 2D Thorium-Argon spectrum with 150 ln/mm,300 ln/mm and 1200ln/mmcross-dispersers in different inclination angle, which can help the user to choose his

appropriate observational setup. The precision of the order location is inside 15-20 pixel invertical direction , so it is recommended to communicate to technicians the order numbersintended to cover too.

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Thorium-Argon spectrum

CCD : E2V CCD47-10

Cross Disperser: 150ln/mm

Filter: OG515

Decker: 1

Angle: -9 30

order N

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CCD : E2V CCD47-10


Filter: OG515

Decker: 1

Angle: -10 00

order N

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CCD : E2V CCD47-10


Filter: OG455

Decker: 1

Angle: -10 30

order N

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CCD : E2V CCD47-10


Filter: No Filter

Decker: 1

Angle: -11 00

order N

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CCD : E2V CCD47-10


Filter: No Filter

Decker: 1

Angle: -7 00

order N

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CCD : E2V CCD47-10


Filter: No Filter

Decker: 1

Angle: -7 30

order N

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CCD : E2V CCD47-10


Filter: No Filter

Decker: 1

Angle: -8 30

order N

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CCD : E2V CCD47-10


Filter: No Filter

Decker: 1

Angle: -9 30

order N

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CCD : E2V CCD47-10


Filter: No Filter

Decker: 1

Angle: -10 30

order N

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55

56

57

58

59


CCD : E2V CCD47-10


Filter: No Filter

Decker: 2

Angle: 0 00

order N

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55

56

57

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59


CCD : E2V CCD47-10


Filter: No Filter

Decker: 2

Angle: 0 00

order N

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CCD : E2V CCD47-10


Filter: No Filter

Decker: 3

Angle: 1 00

order N

52

53

54

55

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CCD : E2V CCD47-10


Filter: No Filter

Decker: 3

Angle: 2 00

order N

49

50

51

52

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CCD : E2V CCD47-10


Filter: No Filter

Decker: 3

Angle: 3 00

order N

46

47

48

49

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39

40


CCD : E2V CCD47-10


Filter: No Filter

Decker: 3

Angle: 7 00

order N

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37

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39


CCD : E2V CCD47-10


Filter: No Filter

Decker: 3

Angle: 8 00

order N

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36

37


CCD : E2V CCD47-10


Filter: No Filter

Decker: 3

Angle: 9 00

order N

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35

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CCD : E2V CCD47-10


Filter: No Filter

Decker: 3

Angle: 10 00

order N

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34


CCD : E2V CCD47-10


Filter: No Filter

Decker: 3

Angle: 11 00

order N

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32

33


CCD : E2V CCD47-10


Filter: No Filter

Decker: 3

Angle: 12 00

order N

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31

30


CCD : E2V CCD47-10


Filter: No Filter

Decker: 3

Angle: 14 00

order N

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CCD : E2V CCD47-10


Filter: No Filter

Decker: 3

Angle: 16 00

order N

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CCD : E2V CCD47-10


Filter: No Filter

Decker: 3

Angle: 18 00

order N

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Th-Ar Atlas

The ThAratlas presented here covers the wavelength region from 3360 to 9430(orders 24-66). The atlas of this spectral region has been performed with two cross-dispersers :

Orders 24-57 (3888 - 9430 ) are done with 150 ln/mm and 100m large slit .

The smallest decker (12.6 arcsec) has been used for decreasing the overlappingof blue orders as much as possible. The redder range (orders 24-33) has beentaken with filter OG515 and changing cross-dispersion angle towards -9.5 o .The orders 33-57 has been taken without filter and cross-dispersion angle near-11.25 o .

Orders 58-66 are done with 300 ln/mm and 150m large slit, cross-dispersionangle near -10.25o .

The exposures used in this atlas were collected in August 2004 and March 2005with E2V CCD47-10 AIMO, a back illuminated 1100 x 1100 CCD Imager. The datawere calibrated, extracted, and dispersion corrected using standard IRAF software. Thetrimming section of CCD was [ 9:1063, 2:1032].

This atlas can be used freely for all three cross-dispersers, as the calibration lampspectra are very similar each other. Only the wavelength ranges are slightly differentand they are given in tables 1, 2,3.

Table 1 shows for each order of 150 ln/mm cross-disperser: the order number (first

column), the initial, ending wavelengths (column 2 and 3 respectively) and average/pxl (last column). Bluer order than 57 are overlapped.

Table 2 shows for each order of 300 ln/mm cross-disperser the order number (firstcolumn), the initial, ending wavelengths (column 2 and 3 respectively) and average/pxl (column 4) and Cross Disperser (CD) angle (last column)..

Table 3 is the similar to Table 2 done for 1200 ln/mm cross-disperser. The redderorders (less than 33) are highly inclined and IRAF has difficulties to extract them.

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CD=150ln/mm slit=100 m

order min () max () disp (/pxl)

24 9234 9431 0.18625 8865 9054 0.17926 8524 8706 0.17227 8208 8383 0.16628 7915 8083 0.16029 7642 7804 0.15430 7387 7544 0.14931 7149 7301 0.14532 6926 7074 0.14033 6716 6860 0.13634 6519 6658 0.132

35 6333 6468 0.12836 6157 6288 0.12537 5990 6118 0.12138 5832 5957 0.11839 5683 5804 0.11540 5541 5659 0.11241 5406 5521 0.10942 5277 5389 0.10743 5154 5264 0.10444 5037 5144 0.102

45 4925 5030 0.10046 4818 4921 0.09847 4715 4816 0.09648 4617 4716 0.09449 4523 4619 0.09250 4432 4527 0.09051 4345 4438 0.08852 4262 4353 0.08653 4181 4271 0.08554 4104 4192 0.08355 4029 4115 0.08256 3957 4042 0.08057 3888 3971 0.079

Table 1. Wavelength ranges of Asiago echelle orders with CD 150 ln/mm taken on 5 March 2005.The bluer part (orders 33-57) is taken changing cross-dispersion angle towards 11.25o and redderrange (orders 24-33) near 9.5 o.

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order min () max () disp (/pxl)

34 6524 6662 0.13135 6337 6471 0.127

36 6161 6291 0.12337 5994 6121 0.12138 5836 5960 0.11839 5687 5807 0.11440 5544 5662 0.11241 5409 5524 0.10942 5280 5393 0.10743 5157 5267 0.10444 5041 5147 0.101

45 4929 5032 0.09946 4822 4923 0.09747 4719 4818 0.09548 4621 4718 0.09349 4526 4621 0.09150 4436 4529 0.08951 4349 4440 0.08752 4265 4355 0.08653 4185 4273 0.08454 4107 4194 0.083

55 4032 4117 0.08156 3960 4044 0.08057 3891 3972 0.07858 3823 3904 0.07859 3759 3838 0.07660 3696 3774 0.07561 3635 3712 0.07462 3577 3652 0.07363 3519 3594 0.07264 3464 3538 0.071

65 3411 3483 0.06966 3360 3431 0.068

Table 3. Wavelength ranges of Asiago echelle orders with 300 ln/mm cross dispersertaken in August 2004. The bluer part (orders 46-66) is taken changing cross-dispersion angle towards -10.25 o and redder range (orders 34-45) near -8.66 o.

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order min () max () disp (/pxl) CD angle33 6703 6848 0.137 1234 6506 6647 0.133 1135 6321 6457 0.129 1036 6145 6278 0.126 937 5978 6107 0.123 938 5821 5947 0.119 839 5672 5794 0.116 740 5530 5649 0.113 741 5395 5511 0.111 642 5266 5381 0.109 643 5144 5254 0.105 5

44 5026 5135 0.104 545 4915 5021 0.101 446 4808 4912 0.099 447 4706 4808 0.097 348 4607 4707 0.095 349 4513 4611 0.093 350 4423 4519 0.09 251 4336 4430 0.088 252 4253 4345 0.087 253 4173 4263 0.086 1

54 4094 4184 0.085 155 4021 4108 0.083 156 3950 4035 0.081 057 3880 3964 0.08 058 3812 3895 0.079 059 3748 3829 0.077 -160 3686 3765 0.076 -161 3625 3704 0.075 -162 3566 3644 0.073 -1

63 3510 3586 0.072 -164 3455 3530 0.071 -1Table 3. Wavelength ranges of Asiago echelle orders with 1200 ln/mm cross disperser

taken on 6 March 2005. The orders are taken at cross-dispersion anglepresented in the last column.

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the echelle user manual

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