fine guidance sensor 2010 hst calibration work shop ed nelan barbara mcarthur stsci

Fine Guidance Sensor2010 HST Calibration Work Shop

Ed NelanBarbara McArthurSTScI

Fine Guidance Sensor2010 HST Calibration Work Shop

Ed NelanBarbara McArthurSTScI

Linda Reed, Art Bradley, Mike Wenz,Ed Kimmer, Matt Lallo, Merle Reinhart, &The Guide Star Acquisition Working Group

UDF Field

guide stars

Hubble Ultra Deep Field412 orbits

20 years of HST Focal Plane

FGS2r2:• FGS2r was replaced due to failing LEDs on its star selector servos, which put guide star acquisitions at risk.

• We now have:• FGS3 (original)• FGS2r2 (new)• FGS1r (1997)

SM4: commissioning & calibrating FGS2r2

On orbit commissioning of FGS2r2 began ~ 2 weeks after HST was released from Atlantis AMA adjustment FGS-FGS2r2 alignment Photometric sensitivity

Long term monitoring of FGS2r2 has been carried out since May 2009. geometric distortion alignment in HST focal plane interferometric response.

Future calibrations being contemplated.

AMA adjustment: aligning the FGS Koesters Prism with the optical axis of HST:

“before” “after”

Alignment of FGS2r2 w.r.t. FGS1r & FGS3

fgs1r

fgs3

fgs2r2

FGS2r2 CommissioningMay – June 2009

Interferometer optical alignment (AMA)

FGS2r2 scale calibration

FGS-FGS2r2 focal plane alignment

Photometric sensitivity

o FGS2r2 geometric distortion calibration• Deferred until instrument stablizes on orbit

• FGS2r2 is routinely used for guiding HST

FGS2r2: monitoring interference fringes

FGS2r2 shows little interferometric evolution during first year in orbit. Due to being in a nitrogen purge from 2002 until 2009?

• Additional adjustment of AMA apparently not needed.• Can proceed with 5-orbit geometric distortion calibration.

FGS1r: ScienceThe Space Telescope Astrometry Team, 10/1996.

April, 1990Space Shuttle Discovery, STS-31

KSC

HST Timeline, 09/2008 – 03/2010

Sept 15/08: NSSC-I FSW upgrade to support SM4 (WFC3 & COS)

HST Timeline, 09/2008 – 03/ 2010


Sept 15/08: JSC closed for the week due to Hurricane Ike. Rumors warn that SM4 may slip due to Ike

HST Timeline, 09/2008 – 03/ 2010



Sept 24/08: NASA announces SM4 launch is Oct 14

HST Timeline, 09/2008 – 03/ 2010




Sept 28/08: HST safes, CU/SDF side-A fails, FGS1r is only HST science instrument operating.

HST Timeline, 09/2008 – 03/ 2010





Sept 30/08: NASA postpones SM4.

HST Timeline, 09/2008 – 03/ 2010






Oct 15/08: NSSC-I switch to side-B

HST Timeline, 09/2008 – 03/ 2010






Oct 15/08: NSSC-I switch to side-B

Oct 16/08: side-B fails returns to operate Oct 29 FGS1r, WFPC2, ACS/SBC only operating instruments until SM4

FGS Timeline 09/2008 – 03/2010 Oct 23/08: Gilliland et al. allocated 175 FGS orbits to collect

one trillion photons from HD 17156. Transit events: Nov 6 & 7, Dec 19 Asteroseismology: Dec 21- Jan 2 (ten-day campaign)

Nov 25/08: Request to re-optimize FGS1r S-curves via AMA submitted to HSTMO and GSFC HST Project. Approved week of 12/01, executed successfully Jan

23,2009

Nov 30/08: Phase 2 Proposal “Calibrating FGS1r OFAD, Second Epoch” submitted. 18 orbits. Needed to execute before December 23 (M35 unavailable

afterward), and before FGS1r AMA re-optimization Executed successfully, Dec 12 – 20, 2008 Previous FGS1r OFAD was Dec 2000.

FGS1r S-curves: significant evolution during 1rst 8 yrs on

orbit

FGS1r S-curves: then, stability, no further changes

FGS1r S-curves: post AMA adjustment

AMA move impact on FGS1r OFAD

Moving FGS1r AMA shifts picklein HST focal plane (~5”).

Four orbits of FGS1r astrometrywere acquired after the AMA moveto re-calibrate FGS1r-FGS alignment.

The relative positions of 16 starswere measured in each orbit.

To measure change in distortion, anidentical set of data were acquiredprior to the AMA move.


Blue symbols show residuals in fit of star position using two “before” orbits.Red symbols show residuals in fit of star positions using two “after” orbits.

residuals ~1.3 mas


Blue symbols show residuals of star positions “before” AMA moverelative to the the stars position measured “after” the AMA move (Blue)

residuals ~4 mas


The difference in the star positions before and after AMA move suggests thatthe mirror move introduced a radial term in the distortion.

FGS1r 6-orbit “mini-OFAD” executed March 2010

Stars from the 1mas “OFAD catalog” in M35 were observed.

FGS1r OFAD updated using 03/2010 observations:

residuals in measured star positions from observations across the AMAmove, using the March 2010 OFAD update.

residuals ~ 3 mas

updated OFAD + radial term fit to all 8 (4 before + 4 after) plates

residuals in measured star positions from observations across the AMAmove, using the March 2010 OFAD update w/radial term in solution.

residuals ~ 2 mas (we want 1.6 mas)

Need for a radial term may indicate that 2010 OFAD was not quite adequate (TBD)

--- may need supplemental visits in December

The “real” way to do OFAD (Dec 2000)

WD 1818+126, the faintest FGS binary

Single scan

V = 16.1 system

pmtxa = 11.3pmtxb = 8.8pmtya = 10.1pmtyb = 13.8

pmtxa_dark = 3.6pmtxb_dark = 1.6pmtya_dark = 3.7pmtyb_dark = 5.9


twenty scans averaged V = 16.1 system


twenty scans averaged,smoothed, and fit to a model V = 16.1 system

dM = 0.9

Mp = 16.5

Ms = 17.4


WD 1818+126 orbit being mapped by FGS1r.

HST has three healthy Fine Guidance Sensors that will serve until the end of the mission.

NIRCam Observationof the HST UDF.

l = 223.55b = -54.451

JWST FGSNIR CameraJ < 18.5see posterby Holfeltz et al.

A

B

fine guidance sensor 2010 hst calibration work shop ed nelan barbara mcarthur stsci

Documents

sm4 launch

hst safes

sm4 wfc3 cossept

optical axis of hst

fsw upgrade

orbit fgs2r2

hurricane ike

beforeafteralignment