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SPACE TELESCOPE SCIENCE INSTITUTE
Summary: 10 October - 29 November 1995

TIPS: 30 November 1995 FOS Keyes

Instrument: Nominal operation Acquisition: 45 successful; 4 failures - all affected by FGS1 LOL problem Science: 29 GO/GTO programs; 3 lost due to LOL problems Calibration: 3 programs (Cycle 5 focus, YBASEs) Publications and Updates: new YBASE settings implemented Other: General TAC support; IS Reviews.


SPACE TELESCOPE SCIENCE INSTITUTE

TIPS: 30 November 1995 FOS Keyes

Instrument Status (10 October - 29 November 1995):
FOS instrumental operation nominal Target Acquisitions: - two failed due to FGS1 loss-of-lock during ACQ/PEAK slews - GHRS science proceeded for one of these instances; the other was lost - two failed due to loss-of-lock during or associated with offset slews - FOS science partially lost for one; entirely lost for other.


SPACE TELESCOPE SCIENCE INSTITUTE
Other:
General TAC support. .

TIPS: 30 November 1995 FOS Keyes


SPACE TELESCOPE SCIENCE INSTITUTE

TIPS: 30 November 1995 FOS Keyes

Cycle 4 Calibration Plan Summary
Program Location of Spectra Dark Monitoring Aperture Wheel Repeatability Focus, X-pitch, Y-pitch Discriminator Test FOS/BL GIM characterization Polarimetry Wavelength Calibration Flat Fields Photometric Monitor, Aperture Throughputs Responsible Koratkar, Dahlem Hayes Dahlem Koratkar, Martin Wheeler Dahlem Allen Dahlem Keyes Bohlin, Lindler, Keyes, Colina CDBS updates HST Workshop CAL/FOS-143 (draft) HST Workshop CAL/FOS-136, -144 HST Workshop Publication CAL/FOS-133 PDB updates CAL/FOS-146 (draft) CAL/FOS-131 Status closed pending closure closed closed - no changes closed - no changes open open pending closure pending closure closed


SPACE TELESCOPE SCIENCE INSTITUTE
Location of Spectra:

TIPS: 30 November 1995 FOS Keyes

FOS/BL shows predictable evolution as function of time. FOS/RD measures show large scatter with no clear trend. CAL/FOS-133 and semi-annual PDB updates.

Aperture Wheel Repeatability:
consistent with pre-launch measures; no indication of mechanical wear upper limit of 0.1 diodes, which includes GIM uncertainty CAL/FOS-131.

Focus, X-pitch, Y-pitch, Discriminator:
no measurable changes during cycle.

FOS/BL GIM Characterization:
analysis in early 1996.


SPACE TELESCOPE SCIENCE INSTITUTE
Wavelength Calibration:

TIPS: 30 November 1995 FOS Keyes

Dispersion relations established for all 10 Cycle 4 epochs. Formal comparison with re-calibrated pre-COSTAR relations now in progress. No substantive changes to date. Final results await re-analysis with new analytical methodology to objectively isolate bad lines from fits (Dahlem and Rosa, forthcoming).

Dark Calibration:
SV and Cycle 1-4 measures all consistent; no temporal trends. clearly dependent upon geomagnetic latitude; no longitude correlation. CAL/FOS-146 (draft).

Flat Field Calibration:
Superflats delivered; applicability is strongly dependent on pointing accuracy. Superspectra characterized for small aperture flat field measures. CAL/FOS-143 (draft) and HST Calibration Workshop. CDBS updates.


SPACE TELESCOPE SCIENCE INSTITUTE

TIPS: 30 November 1995 FOS Keyes

Photometric Monitor and Aperture Throughputs:
Observationally derived calibration for all apertures except bars and 0.1-PAIR Calibration system accurate to <3% for well-centered observations. CAL/FOS-136, CAL/FOS-144, and HST Calibration Workshop. CDBS updates.

Polarimetry Calibration:
FOS/BL linear polarization limiting accuracy currently 0.7% - goal of 0.2% with further calibration. FOS/RD linear polarization limiting accuracy of 1-1.5% - improvement may be possible for 1.0 aperture only. 4.3 aperture should no longer be used for polarimetry ONLY FOS/BL should be calibrated in Cycle 5.


SPACE TELESCOPE SCIENCE INSTITUTE
ACQ/PEAK Scan Pattern
21 20 11 10 1 22 19 12 9 2 23 18 13 8 3 24 17 14 7 4 25 16 15 6 5

typical 0.3 aperture, step-size=0.17 ACQ/PEAK PSF sampling
.01 .02 .01 .033 .02 .033 1.000 .033 .01 .02 .033 .02 .01