HUBBLE SPACE TELESCOPE

            DAILY REPORT #2940

PERIOD COVERED:  0000Z (UTC) 08/20/01 - 0000Z (UTC) 08/21/01

Daily Status Report as of 233/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Two Sets of STIS/CCD 8864 (CCD Dark Monitor-Part 2)

        The Space Telescope Imaging Spectrograph (CCD) was used to monitor 
the darks for the CCD.  The proposal completed nominally.

    1.2 Completed Five Sets of WF/PC-2 8935 (Cycle 10 Standard Darks)

        The WF/PC-2 was used to obtain dark frames every week in order to 
provide data for the ongoing calibration of the CCD dark current rate, and 
to monitor and characterize the evolution of hot pixels.  Over an extended 
period these data will also provide a monitor of radiation damage to the 
CCDs.  The proposal completed with no reported problems.

    1.3 Completed STIS/CCD 9128 (A Snapshot Survey of Absorption Lines from 
High Velocity Clouds in the Milky Way)

        The Space Telescope Imaging Spectrograph (CCD) was used to search 
for Mg II and Mg I absorption from Galactic High Velocity Clouds {HVCs} 
along the sightlines of 51 of the brightest QSOs, BL Lacs and Seyfert 2 
galaxies in the sky.  The observations completed with no rpeorted problems.

    1.4 Completed STIS/CCD 8865 (Bias Monitor-Part 2)

        The Space Telescope Imaging Spectrograph (CCD) was used to monitor 
the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1, and 1x1 at 
gain = 4, to build up high-S/N superbiases and track the evolution of hot 
columns.  The proposal completed with no anomalous activity.

    1.5 Completed STIS/CCD/MA1 8306 (Lyman Alpha Clouds toward PKS1302-102)

        The Space Telescope Imaging Spectrograph (CCD and MA1) was used to 
conduct high spectral resolution observations of the low-redshift quasar 
PKS1302-102, whose line of sight comprises ~20 Lyman Alpha absorbers with 
HI column densities in excess of 10^14 cm^- 2.  The observations completed 
nominally.

    1.6 Completed Two Sets of WF/PC-2 9244 (POMS Test Proposal: WFII 
Parallel Archive Proposal Continuation)

        The WF/PC-2 was used to perform a generic target version of the 
Archival Pure Parallel program.  The program will be used to take parallel 
images of random areas of the sky, following the recommendations of the 
Parallels Working Group.  The observations completed with no anomalous 
activity.

    1.7 Completed Two Sets of WF/PC-2 8828 (Cycle 9 Supplemental Darks pt3/3)

        The WF/PC-2 was used to obtain three dark frames every day to 
provide data for monitoring and characterizing the evolution of hot 
pixels.  The proposal completed with no reported problems.

    1.8 Completed WF/PC-2 8939 (Cycle 10 Internal Monitor)

        The WF/PC-2 was used to calibrate the internal monitor, to be run 
weekly to monitor the health of the cameras.  No problems were encountered.

    1.9 Completed WF/PC-2 9043 (Cepheid Distances to Early-type Galaxies)

        The WF/PC-2 was used to continue observations in the HST Key 
Project on the Extragalactic Distance Scale and the HST project on the 
"Calibration of Nearby Type Ia Supernovae'' that have greatly improved our 
knowledge of the Hubble Constant by providing a solid zero point for the 
Tully- Fisher {TF} relation and Type Ia Supernovae {SNIa}.  However, severe 
inconsistencies remain for distance estimators to early-type galaxies such 
as surface brightness fluctuations {SBF}, the planetary nebula luminosity 
function {PNLF}, the fundamental plane {FP}, and the globular cluster 
luminosity function {GCLF}.  As a result, the distance to the Virgo cluster 
core remains uncertain by as much as 20 determination is directly affected 
by a lingering 0.1 mag {5 uncertainty in the photometric calibration of the 
WFPC2.  Resolving these issues is essential not only to firm up the 
extragalactic distance scale, but also to understand the mass and velocity 
structure of the local universe. SBF in particular is emerging as the 
method of choice for mapping local velocity fields to 10, 000 kms because 
it offers an order of magnitude less Malmquist bias than TF, and SNIa are 
too rare to study large scale flows effectively.  This project will tighten 
the photometric calibration of the WFPC2, and provide a solid Cepheid 
calibration for SBF and PNLF.  The observations completed nominally.

    1.10 Completed STIS/CCD 8841 (Hot Pixel Annealing C9)

        The Space Telescope Imaging Spectrograph (CCD) was used to improve 
the effectiveness of the CCD hot pixel annealing process.  This is assessed 
by measuring the dark current behavior before and after annealing and by 
searching for any window contamination effects.  In addition CTE 
performance is examined by looking for traps in a low signal level 
flat.  The observations completed with no reported problems.

    1.11 Completed Two Sets of WF/PC-2 8867 (Gamma-Ray Bursts: Discovering 
The Progenitors And Understanding The Explosion - Visits A0-R0)

        The WF/PC-2 was used to observe a gamma-ray burster, 
GRB000131.  Gamma-ray burst astronomy, one of the most active and exciting 
frontiers in astrophysics, is now entering a critical stage -- with 
dramatic leaps in understanding of these events, as well as new 
discoveries.  Improvements in triggering and positioning accuracy provided 
by the SAX and HETE-2 gamma-ray satellites will allow entirely new classes 
of events to be studied.  Given the recent progress in this field, the 
proposers are now in a position to design precision, broadband measurements 
that can provide quantitative information on the as-yet unknown energy 
sources, the explosion geometry, and the surrounding medium.  In 
particular, the growing evidence of an intimate connection between SNe and 
GRBs can be definitively tested.  The proposal completed with no reported 
problems.

    1.12 Completed WF/PC-2 9135 (A New High-Z Galaxy Cluster with 
Extraordinary Lensed Arcs From Multiple Sources)

        The WF/PC-2 was used to observe strong lensing by a relatively high 
redshift {z~0.7} cluster in the Red-Sequence Cluster.  This lens system has 
more bright arcs, with better cluster azimuthal coverage than examples of 
lower z lenses previously imaged.  At least 4 separate arcs are detected in 
our initial survey data, at 3-4 different cluster-centric radii and hence 
likely corresponding to at least 3 different background sources at 3 
different redshifts.  Moreover, these arcs are relatively bright and hence 
redshifts should be readily obtainable using 8m class telescopes.  All 
observations completed normally.

    1.13 Completed FGS/1 9169 (An Interferometric Harvest of Double 
Degenerates)

        Fine Guidance Sensor #1R was used to observe the white dwarf mass 
and age distributions that hold clues to the star formation history of our 
Galaxy and the age of the disk.  No problems were reported.

    1.14 Completed WF/PC-2 9042 (An Archive To Detect The Progenitors Of 
Massive, Core-Collapse Supernovae)

         The WF/PC-s was used to search for supernovae which have massive 
star progenitors.  The already extensive HST archive and high-resolution 
ground-based images of galaxies within ~20 Mpc enables us to resolve and 
quantify their individual bright stellar content.  As massive, evolved 
stars are the most luminous single objects in a galaxy, the progenitors of 
core-collapse supernovae should be directly detectable on pre-explosion 
images.  One Type II progenitor has been observed this year, and the 
investigators have proposed a short, companion WFPC2 proposal to confirm 
this candidate and identify a second.  The observations completed nominally.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions:  9
Successful:  9

  Scheduled Re-acquisitions:  5
Successful:  5

    2.2 FHST Updates:
Scheduled: 22
Successful: 22

    2.3 Operations Notes:

        A meeting concerning the recent motor current jump to 196.0 mAmps 
for gyro #3 was held yesterday.  In the short term, the CCS ground 
operational limits have been adjusted to 200 mAmps in order to catch 
another jump.  Flight software limits for motor current, now set at 300 
mAmps for 90 seconds, are acceptable.  PCS SEs have issued an operations 
request to power on gyro #1 should a zero-gyro sunpoint (ZGSP) entry 
occur.  Approved SAC loads have been prepared for a 1, 4, 2, 6 (with 6 in 
shadow mode) gyro configuration.  PCS SEs is researching archived data to 
compare this and other motor current jumps (which were probable step 
functions) with the gyro #5 failure (which was a jump with an 
overshoot).  Other analysis is ongoing.

        Using ROP SR-1A, the SSR EDAC error counter was cleared four times.

        The ephemeris load was uplinked at 233/0056Z as directed by ROP DF-7A.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Flight software 2.0B RAM installation, 2.0B EEPROM, 2.0C RAM 
installation and 2.0C EEPROM installations are scheduled incrementally for 
later today and for the following two days.  Should further problems arise 
with gyro #3, these installations would be postponed.

        Continuation of normal science observations and calibrations.

/CAW