HUBBLE SPACE TELESCOPE

   DAILY REPORT #2613

PERIOD COVERED:  0000Z (UTC) 04/28/00 - 0000Z (UTC) 05/01/00

Daily Status Report as of 122/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Three Sets of 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.

    1.2 Completed 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.

    1.3 Completed Four 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.

    1.4 Completed Four 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.

    1.5 Completed STIS/CCD/MA1/MA2 8280 (Origins, Structure and Evolution 
of Magnetic Activity in the Cool Half of the H-R Diagram: A STIS Survey)

        The Space Telescope Imaging Spectrograph (CCD, MA1 and MA2) was 
used to make observations of star HD204867 to carry out part of a major 
ultraviolet spectral survey of "coronal" late-type stars.  A wavelength 
calibration image was also taken.  The observations were executed as 
scheduled, and no anomalies were noted.

    1.6 Completed Three Sets of WF/PC-2 8805 (POMS Test Proposal: WFII 
Parallel Archive Proposal Continuation)

        The WF/PC-2 was used to perform a generic target version of the 
WFPC2 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.  The proposal completed with no reported problems.

    1.7 Completed WF/PC-2/STIS/CCD/MA1/MA2 8256 (Deep Helium-Mixing and the 
Ultraviolet Spectra of Hot Horizontal Branch Stars)

        The WF/PC-2 and The Space Telescope Imaging Spectrograph (CCD, MA1 
and MA2) were used to make observations of globular cluster NGC-6752 in 
order to study the deep helium-mixing and the ultraviolet spectra of hot 
horizontal branch stars.  There is now good evidence that the luminosities 
and gravities of hot horizontal branch stars in globular clusters are not 
correctly described by canonical models of core helium- burning stars.  A 
wavelength calibration image was also taken.  The observations were 
executed as scheduled, and no anomalies were noted.

    1.8 Completed STIS/MA1 8426 (Cycle 8 MAMA Dark Measurements)

        The Space Telescope Imaging Spectrograph (MA1) was used to make a 
routine Cycle-8 MAMA dark noise calibration measurement.  This proposal 
will provide the primary means of checking on the health of the MAMA 
detectors.  This is done through frequent monitoring of the background 
count rate.  The observations were completed as planned, and no problems 
were reported.

    1.9 Completed STIS/CCD 8803 (Focus Calibration Program)

        The Space Telescope Imaging Spectrograph (CCD) was used to monitor 
the HST focus.  The HST focus drifts slowly and perhaps undergoes slips of 
a few microns at random times.  This focus monitoring program can provide 
evidence of a likely problem with the focus, but does not provide 
sufficient data upon which to act in a short period of time.  This 
two-orbit program obtains a large amount of high signal to noise focus data 
sufficient for accurately defining the HST focus.  The program completed 
nominally.

    1.10 Completed FGS 8527 (Near Term Stability)

        FGS-2R was to be used to determine the near term stability of the 
instrument.  However, the acquisition and re-acquisition failed as detailed 
in HSTARs 7581 and 7582, and the take data flag remained down.

    1.11 Completed Two Sets of 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.

    1.12 Completed Six 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.

    1.13 Completed Two Sets of STIS/CCD 8202 (Bright Quasar Close Lensing 
Search)

        The Space Telescope Imaging Spectrograph (CCD) was used to make 
observations of HCLQ0517-4 and HCLQ2227-2 as part of a second generation 
survey to search for bright lensing quasars.  With the restored PSF, new 
images will be considerably more sensitive to the presence of both close 
separation and faint lens components, and because STIS reaches two 
magnitudes fainter the PC, the new snapshot images will have much greater 
dynamic range.  The observations were executed as scheduled, and no 
anomalies were noted.

    1.14 Completed STIS/CCD 8789 (Probing the Outskirts of an Extrasolar 
Planet: Photometry and Spectroscopy)

        The Space telescope Imaging Spectrograph (CCD) was used to observe 
HD 209458, the first extrasolar planet known to transit the disk of its 
parent star, providing unique probes of this system for moons, rings and 
atmospheric composition that are unlikely to be feasible with ground-based 
observations.  The proposal completed normally, with no reported problems.

    1.15 Completed STIS/CCD 8647 (Black Hole Accretion Outbursts In Soft X- 
Ray Transients)

        The Space Telescope Imaging Spectrograph (CCD) was used to make UV 
observations of soft X-ray transient {SXT} XTE-J1118 . This is part of an 
extensive multiwavelength target of opportunity campaign to monitor newly 
discovered SXTs in outburst and throughout the subsequent decline.  Recent 
work establishes that a high proportion of SXTs harbor black holes, so 
these observations provide an unrivalled opportunity to obtain high quality 
data from an accreting black hole.  UV data is a keystone of this 
multiwavelength campaign because the disk regions of interest radiate 
predominantly in the UV.  Emission lines will give the ability to probe the 
kinematics of the inner disk region.  The relative strengths of the 
reprocessed X-ray flux emitted in the UV will be examined, and the UV flux 
generated by viscous heating in the accretion flow.  Multiwavelength 
observations will probe the physics of the accretion flow throughout the 
outburst.  The observations will yield detailed quantitative tests of the 
models for SXT outbursts.  The new STIS/MAMA capability to perform UV 
spectroscopy with 125 microsecond time resolution will be exploited.  A 
proven HST/RXTE echo-mapping experiment will measure the size of the 
reprocessing regions in the accretion disk, and thus probe morphology 
changes as the decline proceeds.  It is unknown what rapid UV variability 
may be found.  Recent RXTE discoveries suggest this may prove a rich source 
of information on the dynamics close to the event horizon.  The 
observations completed with no reported problems.

    1.16 Completed STIS/CCD/MA1/MA2 8188 (Snapshot Spectroscopic Diagnostic 
Survey of the Symbiotic Stars)

        The Space Telescope imaging Spectrograph (CCD, MA1 and MA2) was 
used to make ultraviolet observations of star RJ105 as part of a snapshot 
spectroscopic diagnostic survey of symbiotic stars.  Using these data we 
will be able to establish meaningful statistical limits on the nature of 
hot component sources of ionization and fundamental wind parameters, which 
are vital steps toward understanding the accretion hydrodynamics and the 
evolutionary status of symbiotic systems.  A wavelength calibration image 
was also taken.  The observations were executed as scheduled, and no 
anomalies were noted.

    1.17 Completed STIS/CCD 8189 (The Source of Gamma Ray Bursts and the 
Nature of their Hosts)

        The Space Telescope Imaging Spectrograph (CCD) was used to make 
high resolution optical and ultraviolet observations of the Gamma Ray 
Burster (GRB) 990510 and its host galaxy.  This comprehensive set of 
observations will provide new insights into the astrophysics of GRBs and 
their high redshift host galaxies.  The observations were completed as 
planned, and no problems were reported.

    1.18 Completed STIS/CCD 8271 (A Snapshot Survey of LMC Planetary 
Nebulae: A Study of Nebular and Late Stellar Evolution)

        The Space Telescope Imaging Spectrograph (CCD) was used to make 
medium-resolution slitless spectroscopy snapshot images of the planetary 
nebulae located in the Large Magellanic Cloud to study the parallel 
evolution of the nebulae and their central stars.  The observations were 
completed as planned, and no problems were reported.

    1.19 Completed STIS/CCD 8261 (Nuclear Structure & Merger-Starburst 
Relation in the Ultraluminous IR Galaxy NGC 6240: II. Kinematics)

        The Space Telescope Imaging Spectrograph (CCD) was used to make 
observations of the nuclear structure and merger starburst relation in the 
ultraluminous infrared galaxy NGC-6240-NU.   This galaxy has tidal tails 
and a double nucleus.  The observations were completed as planned, and no 
anomalies were reported.

    1.20 Completed WF/PC-2 8263 (Snapshots of Sub-mJy Starburst Galaxies)

        The WF/PC-2 was used to make observations of the starbursting 
galaxy GAL-130251.  Some of the most ambitious and widely cited 
extragalactic observations in recent years have been the constraints made 
on the star formation history of the Universe.  The observations were 
completed as planned, and no anomalies were reported

    1.21 Completed WF/PC-2/STIS/CCD/MA2 7334 (The Primordial Abundance of 
Deuterium From a Metal-Poor Damped Lyman Alpha System)

        The WF/PC-2 and the Space Telescope Imaging Spectrograph (CCD and 
MA2) were used to make observations of the quasar Q2206-1958 to study the 
primordial abundance of deuterium from a metal-poor damped Lyman-Alpha 
system.  It should be possible to detect D absorption in many Lyman series 
lines and the chance of contamination by interloper H clouds is reduced by 
a factor of > 150.  A wave length calibration image was also taken.  The 
observations were executed as scheduled, and no anomalies were noted.

    1.22 Completed STIS/CCD/MA1 8279 (Cataclysmic Variable Disk Winds: A 
High Time and Spectral Resolution Study of  Flow Inhomogeneity)

        The Space Telescope Imaging Spectrograph (CCD and MA1) was used to 
observe disks and disk winds which are found in many astrophysical 
settings.  The proposal completed nominally

    1.23 Completed WF/PC-2 7374 (Probing Low Density Cluster Environments 
at Moderate-to-High Redshifts)

        The WF/PC-2 was used to make observations of the galactic cluster 
Gal-Clus-0.  Recent HST WF/PC-2 images of rich clusters at moderate-to-high 
redshifts have revealed that morphological information is a crucial 
ingredient in understanding the physical processes responsible for the 
evolution of the galaxy population in clusters.  The observations were 
executed as scheduled, and no anomalies were noted.

    1.24 Completed STIS/CCD 8209 (The Complex Circumstellar Environment of 
the Massive Contact Binary RY Scuti)

        The Space Telescope Imaging Spectrograph (CCD)  was used to observe 
HD169515, a very massive and luminous evolved contact binary system 
surrounded by an unusual nebula that is only a few arcseconds in 
extent.  The observations completed nominally.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 20
Successful: 18
  Scheduled Re-acquisitions: 27
Successful: 26

        Per HSTAR 7581, the acquisition scheduled at 119/124200Z failed, as 
did the re-acquisition at 119/1347Z.  Then, according to HSTAR 7582, the 
acquisition at 119/140900Z also failed.  The proposal detailed in 1.10 was 
affected.

    2.2 FHST Updates:
Scheduled: 55
Successful: 55

    2.3 Operations Notes:

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

        SSA transmitter 2R was turned on and off for eight intervals as 
directed by ROP IC-2.

        Per ROP NS-5, an NSSC-1 engineering report was obtained at 119/1359Z.

        An unplanned time tag slew was performed at 119/1452Z per an 
operations request.

        A TTR was written for an MA return drop-out at 120/154710Z.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW