HUBBLE SPACE TELESCOPE

   DAILY REPORT #2597

PERIOD COVERED:  0000Z (UTC) 04/06/00 - 0000Z (UTC) 04/07/00

Daily Status Report as of 098/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed WF/PC-2 8214 (The Evolution of Globular Cluster Systems 
In Early-Type Galaxies)

        The WF/PC-2 was used to measure structural parameters {core radii 
and concentrations} of globular clusters in three early-type galaxies using 
deep, four-point dithered observations.  The observations completed nominally.

    1.2 Completed Two Sets of WF/PC-2 8460 (Cycle 8 Supplemental Darks pt2/3)

        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 observations completed with no reported problems.

    1.3 Completed WF/PC-2 8203 (Dwarf Busting in Abell 868)

        The WF/PC-2 was used to to identify and characterize the 
morphological nature of the dwarf galaxy population{s} responsible for the 
steep upturn seen in Abel 868's luminosity function.  While similar upturns 
have been reported in many clusters, the specifics of the dwarf population 
remain unknown as these objects cannot be resolved from the ground.  What 
type of dwarf galaxies are they ?  Is there more than one population 
contributing ?  How are they clustered ?  These observations are intended 
to answer these questions.  The observations were completed, and no 
problems were reported.

    1.4 Completed Two Sets of WF/PC-2 8457 (UV Earth Flats)

        The WF/PC-2 was used to obtain a series of Ultraviolet Earth 
flats.  The observations were completed with no reported problems.

    1.5 Completed Two Sets of STIS/CCD 8410 (STIS CCD Hot Pixel Annealing C8)

        The Space Telescope Imaging Spectrograph (CCD) was used to assess 
the effectiveness of the CCD hot pixel annealing process 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 were 
completed as planned, and no anomalies were reported.

    1.6 Completed WF/PC-2 8444 (WF/PC-2 CYCLE-8 Internal Monitor)

        The WF/PC-2 was used to make a bias, and an internal flat, 
observation as part of a Cycle-8 monitoring program to monitor the health 
of the cameras.  A variety of internal exposures are obtained in order to 
provide a monitor of the integrity of the CCD camera electronics in both 
bays {gain 7 and gain 15}, a test for quantum efficiency in the CCDs, and a 
monitor for possible buildup of contaminants on the CCD windows.  The 
observations were executed as scheduled, and no anomalies were noted.

    1.7 Completed Two Sets of WF/PC-2 8230 (Snapshot Survey of Dynamically 
Close Galaxy Pairs from z=0.1 to z=0.5)

        The WF/PC-2 was used to make snapshot survey observations of 
galactic cluster Gal-Clus-0.  This is to obtain snapshot images of a large, 
well-defined, and dynamically selected sample of close galaxy pairs at 
moderate redshift.  The observations were executed as scheduled, and no 
anomalies were noted.

    1.8 Completed Two Sets of STIS/CCD 8549 (POMS Test Proposal: 
Non-Scripted Parallel Proposal Continuation I)

        The Space Telescope Imaging Spectrograph (CCD) was used to make low 
galactic latitude, non-scripted parallel observations as part of a POMS 
test proposal.  The observations were completed as planned, and no 
anomalies were reported.

    1.9 Completed Two Sets of WF/PC-2 8448 (Cycle 8 INTFLAT Sweeps, VISFLAT 
Mini-Sweep, and Linearity Test)

         The WFPC2 was used to monitor the pixel to pixel flatfield 
response and the VISFLAT lamp degradation, as well as detect any possible 
changes due to contamination.  As described in 2.1 and HSTAR 7568, the 
acquisition for the final iteration of this proposal failed, and the take 
data flag remained down, affecting three observations.  Otherwise, the 
observations completed nominally.

    1.10 Completed STIS/CCD/MA1/MA2 7764 (Activity on the Edge of 
Convection: The Atmosphere of Canopus {F0 Ib-II})

        The Space Telescope Imaging Spectrograph (CCD, MA1 and MA2) was to 
be used to make observations of the star Canopus (a.k.a., HD45348 or Alpha 
Car), the nearest {96 pc} supergiant star.  Canopus is an early F 
supergiant with an extremely thin convection zone, yet it shows significant 
X-ray emission from a very hot corona.  A wavelength calibration image was 
also to be taken.  As described in 2.1 and HSTAR 7568, the acquisition for 
this proposal failed, and the take data flag remained down.  Twenty-one 
observations were affected.

    1.11 Completed WF/PC-2 8090 (POMS Test Proposal: WF-II Parallel Archive 
Proposal Continuation)

        The WF/PC-2 was to be used in the parallel mode to make some low 
galactic latitude archive observations.  As described in 2.1 and HSTAR 
7568, the acquisition for this proposal failed, and the take data flag 
remained down.  Five observations were affected.

    1.12 Completed WF/PC-2 8193 (Comparing the Hosts of High-Z Radio-Quiet 
Quasars to Lyman Break Galaxies)

        The WF/PC-2 was used to try to determine the underlying causes of 
the rapid cosmological evolution of the quasar population that is a mystery 
around which is woven many different strands of contemporary 
cosmology.  The proposal completed nominally.

    1.13 Completed STIS/CCD 8437 (Dark Monitor-Part 2 C8)

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

    1.14 Completed STIS/CCD 8439 (Bias Monitor-Part 2 C8)

        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 reported problems.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 7
Successful: 6
  Scheduled Re-acquisitions: 8
Successful: 7

        The acquisition scheduled at 097/145753Z failed to RGA mode at 
097/150151Z when the search radius limit was exceeded on both FGS-1 and 
FGS-2.  FHST maps taken before the failure were nominal.  A map performed 
at 097/1537Z showed small vehicle errors.  The subsequent re-acquisition at 
097/1636Z also failed.  HSTAR 7568 was written.  The proposals described in 
1.9, 1.10, and 1.11 were affected.

        Per HSTAR 7570, the acquisition at 097/235030 defaulted to fine 
lock backup on FGS-3 only when the scan step limit was exceeded on 
FGS-2.  Two proposals, WF/PC-2 8114 and STIS 8439, both occurring during 
the period of the next report, may have been affected.

    2.2 FHST Updates:
Scheduled: 18
Successful: 18

    2.3 Operations Notes:

        The load for the Target of Opportunity Observation, STIS proposal 
8747, was uplinked mid-morning yesterday.

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

        STIS error flags were cleared at 097/1629Z per ROP NS-12.  This 
relates to the acquisition problems with the proposal described in 1.10..

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW