HUBBLE SPACE TELESCOPE

   DAILY REPORT #2596

PERIOD COVERED:  0000Z (UTC) 04/05/00 - 0000Z (UTC) 04/06/00

Daily Status Report as of 097/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 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.

    1.2 Completed WF/PC-2 8338 (The Evolution of the Host Galaxies of 
Powerful Radio Sources)

        The WF/PC-2 was used to make observations of the host galaxy of the 
powerful radio source known as MRC2135-20.  A combined data set of radio 
galaxies and quasars will allow powerful tests of the relationship between 
radio galaxies and quasars and the evolution of the host galaxies of 
powerful radio sources over a wide range of look-back times.  The 
observations were executed as scheduled, and no anomalies were noted.

    1.3 Completed Three 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.

    1.4 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.

    1.5 Completed FGS 8392 (The Masses of the O-type Binary 15 Monocerotis 
- Continued)

        The Fine Guidance Sensors were used to perform astrometric 
observations of the binary system relative to nearby reference stars that 
are also observable in the FGS FOV.  This will lead to a determination of 
the mass of each component.  Both radial velocity and astrometric 
measurements are scant at present, but the system is now close to 
periastron and continued spectroscopic and astrometric monitoring will lead 
to a definitive orbit and yield important information about the masses of 
O-type stars.  FGS measurements of separation, position angle, and 
magnitude difference {begun in Cycle 5} are needed to bridge the gap 
between current speckle observations and the new generation of optical 
interferometers.  The proposal completed with no reported problems.

    1.6 Completed Four Sets of WF/PC-2 8090 (POMS Test Proposal: WF-II 
Parallel Archive Proposal Continuation)

        The WF/PC-2 was used in the parallel mode to make some low galactic 
latitude archive observations.  The program will be used to take parallel 
images of random areas of the sky.  The observations were executed as 
scheduled, and no anomalies were noted.

    1.7 Completed Two Sets of STIS/CCD 8437 (Dark Monitor-Part 2 C8)

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

    1.8 Completed STIS/CCD 8217 (Tests of Stellar Models Using Four 
Extremely Massive Spectroscopic Binaries in the R136 Cluster)

        The Space Telescope Imaging Spectrograph (CCD) was used to observe 
four non-interacting double-lined spectroscopic binaries discovered in the 
R136 cluster by the Cycle 6 FOS spectroscopy.  The proposal completed 
nominally.

    1.9 Completed WF/PC-2 8059 (POMS Test Proposal: Targeted Parallel 
Archive Proposal)

        The WF/PC-2 was used to observe the parallel opportunities 
available in the neighborhood of bright galaxies are treated in a slightly 
different way from the normal pure parallels.  Local Group galaxies offer 
the opportunity for a closer look at young stellar 
populations.  Narrow-band images in F656N can be used both to identify 
young stars via their emission lines, and to map the gas distribution in 
star-forming regions.  The observations completed nominally.

    1.10 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.  The observations completed nominally.

    1.11 Completed STIS/MA1/MA2 8201 (Ultra-luminous Infrared Galaxies)

        The Space Telescope Imaging Spectrograph (MA1 and MA2) was used to 
make ultraviolet observations of the ultra-luminous infrared galaxy 
IRAS13183.  Ultra-luminous Infrared Galaxies are the most luminous galaxies 
known in the local universe, and are predominantly powered by massive star 
formation.  The observations were executed as scheduled, and no anomalies 
were noted.

    1.12 Completed Two Sets of WF/PC-2 8445 (WF/PC-2 Cycle 8 Earth Flats)

        The WF/PC-2 was used to make Cycle 8 Earth flat calibration 
observations.  This is to obtain sequences of earth streak flats to 
construct high quality flat fields for the WF/PC-2 filter set.  The 
observations were executed as scheduled, and no anomalies were noted.

    1.13 Completed WF/PC-2 8184 (The Origin of cD Envelopes)

        The WF/PC-2 was used to observe cD galaxies which are known to 
known to be present in approximately 20 percent of all galaxy 
clusters.  Located at the dynamical centers of their host cluster or 
subcluster, these supergiant elliptical galaxies show extended, diffuse 
stellar envelopes which trace the gravitational potential of the 
surrounding cluster.  The observations completed with no reported problems.

    1.14 Completed 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.

    1.15 Completed WF/PC-2 8146 (A Search for Binary L-Dwarfs)

        The WF/PC-2 was used to search for close binaries amongst the 
sample of 37 low-temperature L dwarfs, identified primarily in the course 
of the DENIS and 2MASS near-infrared surveys.  The observations completed 
with no reported problems.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions:  5
Successful:  5

  Scheduled Re-acquisitions: 10
Successful: 10

    2.2 FHST Updates:
Scheduled: 13
Successful: 13

    2.3 Operations Notes:

        A target of opportunity observation (TOO) has been decided 
upon.  Accordingly, the load scheduled to begin execution mid-day 097 was 
re-run.  This load will be uplinked at approximately 097/1300Z.  During 
this load, at approximately 099/1200Z, STIS proposal 8647 (Black Hole 
Accretion Outbursts in Soft X-Ray Transients), the TOO, will begin.

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

        The NSSC-1 status buffer was dumped at 096/2107Z, using ROP NS-3.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW