HUBBLE SPACE TELESCOPE

   DAILY REPORT #2628

PERIOD COVERED:  0000Z (UTC) 05/19/00 - 0000Z (UTC) 05/22/00

Daily Status Report as of 143/0000Z

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.  During the second iteration of this proposal, the acquisition 
re-acquisition failures described in 2.1 and HSTAR 7607 occurred, affecting 
all observations in that iteration.  Otherwise, the proposal completed with 
no further reported problems.

    1.2 Completed Seven 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.  During the fourth iteration of this proposal, the acquisition 
re-acquisition failures described in 2.1 and HSTAR 7607 occurred, affecting 
all observations in that iteration.  Otherwise, the observations completed 
with no further reported problems.

    1.3 Completed Three Sets of STIS/CCD/MA1 8241 (A Snapshot Survey of 
Interstellar Absorption Lines)

        The Space Telescope Imaging Spectrograph (CCD and MA1) was used to 
make high resolution Echelle spectrographic observations of the standard 
ultraviolet stars BD+25D2534, HD14894, HD79931 as part of a snapshot survey 
of interstellar absorption lines.  Wavelength calibration images were also 
taken.  The observations were executed as scheduled, and no anomalies were 
noted.

    1.4 Completed Two Sets of WF/PC-2 8118 (Snapshot Survey of Galactic 
Globular Clusters0

        The WF/PC-2 was used to make observations of crowded centers of 
globular clusters {GCs} which have produced intriguing discoveries of new 
phenomena, most of which are not understood theoretically. This is a 
continuation of a Cycle 7 snapshot proposal, to extend such work to a much 
larger portion of the Galactic GC system.  The observations completed 
nominally, with no reported problems.

    1.5 Completed Five 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.

    1.6 Completed WF/PC-2 8124 (The Stellar Initial Mass Function of 
Globular Clusters)

        The WF/PC-2 was used to observe the mass functions of homogeneous 
old stellar populations.  Those for which reliable mass functions have been 
determined already, however, have generally been subject to dynamical 
evolution {relaxation, escape of stars, and tidal shocks}, so that the 
observed mass function is not primordial.  We have therefore examined 
tables of properties of globular clusters in order to choose those that are 
least likely to have suffered from relaxation, escape, and tidal 
shocks.  There were no reported problems.

    1.7 Completed Six Sets of STIS/CCD 8808 (POMS Test Proposal: STIS 
Non-Scripted Parallel Proposal Continuation III)

        The Space Telescope Imaging Spectrograph (CCD) was used to make 
non-scripted, parallel observations as part of a POMS test proposal.  The 
observations completed with no anomalous activity.

    1.8 Completed 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 WF/PC-2 8270 (Proper Motion of the Leo II Dwarf Spheroidal)

        The WF/PC-2 was used to continue the investigation into the proper 
motion of distant satellites of the Milky Way with a series of HST 
snapshots around faint galaxies within the Leo II astrometric field.  A 
proper motion for Leo II will be determined by combining images from 111 
Palomar 200" photographic plates taken by Baade between 1950-1959 with the 
HST snapshots.  Only with the fine pixel scale of HST can we realistically 
hope to match the exquisite Baade images, which were all taken on the very 
best nights from a decade of Baade's allotment of about forty 200 arcsecond 
nights a year.  The observations completed with no reported problems

    1.10 Completed WF/PC-2 8325 (Galaxy Evolution in Low-Density 
Environments: WFPC2 Imaging of Poor X-Ray Clusters at z=0.2-0.3)

        The WF/PC-2 was used to obtain high quality morphological 
information on galaxies within nine X-ray-selected poor clusters at 
z=0.2-0.3. These morphologies will be combined with information on the 
stellar populations of the galaxies from our on-going spectroscopic survey 
of these systems to provide a complete view of the morphological and 
spectral evolution of galaxies within these clusters.   The observations 
completed nominally.

    1.11 Completed Two Sets of STIS/CCD 8489 (Searching for the Hydrogen 
Reionization Edge of the Universe at 5HST)

        The Space Telescope Imaging Spectrograph (CCD) was used to observe 
36 parallel orbits {4--5 fields of 5--8 orbits each} to constrain the H 
Lyman-edge in emission that marks the transition from a neutral to a fully 
ionized IGM.  This edge is due to recombination from the H Lyman series and 
Lyman continuum, and can be used to constrain zion, one of the most 
important unknown quantities in large scale structure and cosmology.  The 
proposal completed nominally.

    1.12 Completed Four Sets of STIS/MA1/MA2 8426 (Cycle 8 MAMA Dark 
Measurements)

        The Space Telescope Imaging Spectrograph (MA1 or MA2) 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.

    1.13 Completed STIS/CCD/MA1/MA2 8265 (Reverberation Mapping of a 
Narrow-Line Seyfert 1 Galaxy)

        The Space Telescope Imaging Spectrograph (CCD, MA1 and MA2) was 
used to monitor the UV spectral variability of the narrow-line Seyfert 1 
{NLS1} galaxy AKN564 at 46 epochs in order to measure the size of the broad 
emission-line region via reverberation-mapping techniques.  This 
measurement, and the virial mass estimate that follows from it, will 
provide a key test of NLS1 models and help determine the physical mechanism 
that underlies the principal component of AGN spectra, the Boroson--Green 
primary eigenvector.  These observations will be undertaken in parallel 
with X-ray and ground-based optical observations that will allow us for the 
first time to explore the multiwavelength variability characteristics of 
this important subclass of active galactic nuclei.  The observations 
completed with no reported problems.

    1.14 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 SS-38 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.

    1.15 Completed Five 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.

    1.16 Completed WF/PC-2/STIS/CCD/MA2 8047 (Observations of Globular 
Cluster Stars)

        The WF/PC-2 and the Space Telescope Imaging Spectrograph (CCD and 
MA2) were to be used to observe the star UIT-1 in the globular cluster 
which has been found to have large helium abundance {Y = 0.67}.  During 
this proposal, the acquisition re-acquisition failures described in 2.1 and 
HSTAR 7607 occurred, affecting all observations.

    1.17 Completed STIS/CCD 8123 (Testing the Stellar Dynamics of Nested 
Bars in NGC 5728)

        The Space Telescope Imaging Spectrograph (CCD) was used to make 
observations of the barred galaxy NGC-5728.  Near infrared images of this 
barred galaxy reveal the existence of an inner bar, twisted by a large 
angle relative to its primary bar.  A wavelength calibration image was also 
taken.  The observations were executed as scheduled, and no anomalies were 
noted.

    1.18 Completed WF/PC-2 7265 (The Metallicity Distribution of the 
Globular Cluster Systems of Giant Elliptical Galaxies)

        The WF/PC-2 was used to make observations of the globular clusters, 
which are located in galaxy NGC-3842-CE. This is to study the metallicity 
distribution of this system.  These observations will have a significant 
impact on our understanding of the origin and nature of globular cluster 
systems in galaxies.  The observations were completed as planned, and no 
problems were reported.

    1.19 Completed STIS/CCD 8228 (The Black Hole Versus Bulge Mass 
Relationship in Spiral Galaxies)

        The Space Telescope Imaging Spectrograph (CCD) was used to make 
observations of the galaxy NGC-5921 in order to study the black hole versus 
bulge mass relationship in spiral galaxies.  A wavelength calibration image 
was also taken.  The observations were executed as scheduled, and no 
anomalies were noted.

    1.20 Completed STIS/CCD/MA1 8139 (Probing an Ancient Thermonuclear 
Runaway on a White Dwarf in a Dwarf Nova)

        The Space Telescope Imaging Spectrograph (CCD and MA1) was used to 
probe the ancient thermonuclear runaway on a white dwarf.  Evidence was 
unexpectedly discovered, based upon two GHRS G160M spectra, of greatly 
elevated abundances of odd-numbered nuclei Phosphorus and Aluminum, as well 
as a Nitrogen-to-Carbon ratio of 10 in the photosphere of the white dwarf 
in the dwarf nova VW Hyons.  This proposal intends to {1} determine the 
first chemical abundances of many odd-numbered proton capture species; {2} 
determine a accurate mass for the white dwarf and; {3} probe changes in the 
accretion belt and surface abundances as a function of time since a 
superoutburst.  The proposal completed nominally.

    1.21 Completed STIS/CCD/MA1 8097 (C IV High Velocity Clouds: Remnants 
of the Local Group?)

        The Space Telescope Imaging Spectrograph (CCD and MA1) was used to 
make observations of two high clouds {HVCs} in the direction of Mrk 509 
that have unusual ionization properties.  The clouds exhibit strong C IV 
absorption with little or no detectable low ion {C II, Si II} absorption or 
H I 21cm emission.  The observations completed nominally.

    1.22 Completed WF/PC-2 8163 (Trapezium Systems and Stellar Jets in 
30-Doradus)

        The WF/PC-2 was used to make observations of the 30-Doradus system 
(both the North and South sections).  30-Doradus is the nearest and best 
resolved extragalactic starbursting region.  The observations were 
completed as scheduled, and no anomalies were reported.

    1.23 Completed WF/PC-2 8247 (Hidden New-Born Massive Stars in Compact H 
II ``Blobs'' of the Large Magellanic Cloud)

        The WF/PC-2 was used to perform high spatial resolution imaging to 
resolve very tight clusters of massive stars at birth in the Large 
Magellanic Cloud.  These are the youngest massive stars accessible to 
direct observations at ultraviolet and optical wavelengths.  The 
observations completed nominally.

    1.24 Completed STIS/CCD 7912 (STIS Parallel Archive Proposal - Nearby 
Galaxies - Imaging and Spectroscopy)
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        The Space Telescope Imaging Spectrograph (CCD) was used to make 
parallel observations of nearby galaxies.  This survey will be useful to 
study the star formation histories, chemical evolution, and distances to 
these galaxies.  These data will be placed immediately into the Hubble Data 
Archive.  The observations were completed as scheduled, and no problems 
were reported.

    1.25 Completed WF/PC-2 8459 (Decontaminations and Associated 
Observations Pt. 2/2)

        The WF/PC-2 was used to perform the monthly decons.  Also included 
are instrument monitors tied to decons: photometric stability check, focus 
monitor, pre- and post-decon internals {bias, intflats, kspots, & darks}, 
and UV throughput checks.  The observations were completed nominally.

    1.26 Completed WF/PC-2 8609 (Host Galaxy Luminosities of the Most 
Luminous QSOs)

        The WF/PC-2 was used to determine the factors that decide whether a 
galaxy is host to a luminous QSO.  Recent evidence indicates that host 
galaxy spheroid mass is a key factor: we want to test the relationship 
between host galaxy and QSO luminosity at the highest feasible QSO 
luminosities by measuring the luminosities and profiles of host galaxies 
for QSOs with -25.8 > M_V > -27.6.  Current data in this area are 
conflicting.  The observations completed with no reported anomalies.

    1.27 Completed STIS/CCD/MA2 8197 (Detection of ^11B/^10B: Part II)

        The Space Telescope Imaging Spectrograph (CCD and MA2) was used to 
make spectrographic observations of star HD94028 to measure the boron 
isotope ratio (i.e., 11B/10B).  A wavelength calibration image was also 
taken.  The observations were completed as planned, and no anomalies were 
reported.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 20
Successful: 19
  Scheduled Re-acquisitions: 23
Successful: 22

        As documented in HSTAR 7607, the acquisition scheduled for 
140/2119Z failed when the search radius limit was exceeded for both FGS-2 
and FGS-3.  The following re-acquisition also failed at 140/230353Z.  The 
proposals detailed in 1.1, 1.2 and 1.16 were affected.

    2.2 FHST Updates:
Scheduled: 46
Successful: 46

    2.3 Operations Notes:

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

        SSA transmitter #2 was turned on and off three times per ROP IC-2.

        The MA transmitter was turned on and off five times as directed by 
ROP IC-1.

        During the weekend, the "B" string FEP hardware was recycled twice 
on day 140.  Early on day 141, a complete "B" string recycle was performed.

        Due to the acquisition/re-acquisition failures described in 2.1, 
the STIS flight software error counter was reset at 140/2247Z as directed 
by ROP NS-12.

        The engineering status buffer (ESB) was dumped and cleared at 
141/0029Z per ROP NS-18A.  Using the same ROP, the ESB high limit was set 
to '1' at 143/0448Z.

        The NICMOS FPA temperature sensor for detector 1 was enabled at 
142/0845Z.

        A TTR was written when GCMR capability was lost in the interval 
142/2223Z to 142/2250Z due to an NCC software problem.  There was no data loss.

        The SSR Autonomous Engineering was set the "start" and then "stop" 
using ROP SR-8A for the interval 142/2320Z to 143/0016Z.  Then at 143/0020 
the 32k engineering stream was commanded to stop recording at 143/0020Z per 
ROP SR-5A.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.
/CAW