HUBBLE SPACE TELESCOPE

   DAILY REPORT #2608

PERIOD COVERED:  0000Z (UTC) 04/21/00 - 0000Z (UTC) 04/24/00

Daily Status Report as of 115/0000Z

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 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.

    1.3 Completed Twelve 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 Five 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 Three 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 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.

    1.7 Completed Five Sets of WF/PC-2 8301 (A Snapshot Survey of X-ray 
Selected Central Cluster Galaxies)

        The WF/PC-2 was used to make snapshot survey observations of the 
x-ray, central cluster galaxies A1084, A2254, RXJ2129.6, Z7160 and 
A1413.  Central cluster galaxies are the most massive stellar systems known 
and have been used as standard candles for many decades.  As described in 
2.1 and HSTAR 7578, the guide star acquisition for the final iteration of 
this proposal failed, affection two observations.  Otherwise, the 
observations were executed as scheduled, and no further anomalies were noted.

    1.8 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.

    1.9 Completed Two Sets of STIS/CCD 8127 (The Homogeneity of Damped 
LyAlpha Systems {and Variability in BAL Systems})

        The Space Telescope Imaging Spectrograph (CCD) was used to 
investigate the damped LyAlpha line at z_abs = 1.6595 in the 
gravitationally lensed Cloverleaf QSO, seen in the composite FOS-G270H 
spectrum of the Cloverleaf.  The observations completed with no reported 
anomalies.

    1.10 Completed Three 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.

    1.11 Completed Six 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.

    1.12 Completed Two Sets of STIS/MA2 8427 (MAMA Fold Analysis for Cycle 8)

        The Space Telescope Imaging Spectrograph MAM2) was used to perform 
a MAMA Fold Analysis Proposal for cycle 8.  There were no reported problems.

    1.13 Completed Two Sets of WF/PC-2 8100 (Calibration of Nearby Type Ia 
Supernovae as Standard Candles: The Next Step)

        The WF/PC-2 was used to continue the calibration experiment for M{ 
max} of type Ia supernovae {SNe Ia} by determining Cepheid distances to 
their parent galaxies.  The proposal completed nominally.

    1.14 Completed Three Sets of STIS/CCD 8796 (POMS Test Proposal: STIS 
Non-Scripted Parallel Proposal Continuation IV)

        The Space Telescope Imaging Spectrograph (CCD) was used in the 
parallel mode to make some low galactic latitude archive observations.  The 
observations were executed as scheduled, and no anomalies were noted.

    1.15 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.

    1.16 Completed STIS/CCD 7912 (STIS Parallel Archive Proposal - Nearby 
Galaxies - Imaging and Spectroscopy)

        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.

    1.17 Completed WF/PC-2 8274 (A Size Survey of Cometary Nuclei)

        The WF/PC-2 was used to make observations of the comet WILD1 as 
part of a size survey of cometary nuclei.  This is part of a program to 
determine the basic physical properties of a large fraction of the 
population of short-period comets.  The observations were completed as 
planned, and no anomalies were reported.

    1.18 Completed WF/PC-2 8153 (Exploring the Luminosity Function near the 
Limit of Hydrogen Burning in Globular Clusters)

        The WF/PC-2 was used to determine the color--magnitude diagram and 
luminosity function of M4-CTR into the neighborhood of the hydrogen-burning 
limit.  Accurate astrometry, over a baseline of a few years, allows an 
excellent proper-motion separation of faint cluster stars from the 
numerically dominant field stars.  The observations completed nominally.

    1.19 Completed WF/PC-2 8174 (Internal Velocity Distribution in Globular 
Clusters, II)

        The WF/PC-2 was used to determine the internal velocity 
distribution of the globular cluster NGC 6205 in its core.  The proposal 
completed with no anomalous activity.

    1.20 Completed STIS/CCD/MA2 8284 (Deep STIS Observations of BALQSO PG 
0946+301)

        The Space Telescope Imaging Spectrograph (CCD and MA2) was used to 
study AGN outflows to determine of the ionization equilibrium and 
abundances (IEA) in broad absorption line {BAL} QSOs.  In the last few 
years it has become clear that partial coverage of the continuum source and 
saturation are common in BALs, and these frustrate attempts to determine 
the IEA from available HST data because of limitations imposed by the S/N 
ratio and spectral coverage. We will re-observe the most suitable BAL IEA 
target: PG 0946+301.  The observation completed with no reported problems.

    1.21 Completed STIS/MA2 8275 (Ultraviolet Snapshots of 3CR Radio Source 
Counterparts at Low Z)

        The Space Telescope Imaging Spectrograph (MA2) was used to make 
ultraviolet snapshot observations of the radio galaxy 3C198.0.  Radio 
galaxies are an important class of extragalactic objects, representing one 
of the most energetic astrophysical phenomena, while extraordinarily useful 
as probes of their environments and of the early Universe.  The 
observations were completed as scheduled, and no anomalies were reported.

    1.22 Completed STIS/CCD/MA1 8785 (Follow-Up of GTO 7577 on M83)

        The Space Telescope Imaging Spectrograph (CCD and MA1) was used to 
follow up on the previous programs on the circum- nuclear starburst of 
M83=NGC5236.  The observations completed nominally.

    1.23 Completed FGS 8465 (Long Term Stability of FGS2R in Transfer Scan 
Mode)

        Fine Guidance Sensor 2R was used to determine the stability of 
FGS2r S-curves which is not certain at this time due to 
desorption.  Changes in S curve morphology and amplitude can potentially 
render the operational calibration database for FG2r obsolete, resulting in 
an unacceptable increase in guide star acquistion failures and HST pointing 
errors.  The data
gathered from these visits will monitor the FGS2r S-curves to allow for a 
predictive assessment of the validity of the FGS2r calibrations and its 
expected performance as a guiding instrument.  The observations completed 
with no reported problems.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 20
Successful: 19

        Per HSTAR 7578, the acquisition scheduled for 114/033213Z failed 
immediately after the transition to fine lock.  The proposal described in 
1.7 was affected.
  Scheduled Re-acquisitions: 28
Successful: 28

    2.2 FHST Updates:
Scheduled: 49
Successful: 48

        Th update at 113/0422Z failed.  Following acquisitions were successful.

    2.3 Operations Notes:

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

        The SSA transmitter was turned on and off nine times per ROP IC-2.

        MA transponder 2 was turned on and off twice as directed by ROP IC-1.

        There were STIS EMC re-tries at 112/192456Z and 114/194252Z.  In 
each case, the STIS flight software error counter was cleared using ROP NS-12.

        The NSSC-1 status buffer was dumped and cleared at 113/2034Z per 
ROP NS-3.

        An SI C&DH error was reset at 114/1730Z.

        SSR-1 was set to record 32k engineering data at 115/0007Z.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW