HUBBLE SPACE TELESCOPE

   DAILY REPORT #2876

PERIOD COVERED:  0000Z (UTC) 05/18/01 - 0000Z (UTC) 05/21/01

Daily Status Report as of 141/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Twelve Sets of WF/PC-2 9244 (POMS Test Proposal: WFII 
Parallel Archive Proposal Continuation)

        The WF/PC-2 was used to perform a generic target version of the 
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 Group.  The re-acquisition failure described in HSTAR 
8229 and 2.1, occurred during the tenth iteration of this proposal, and the 
take data flag remained down.  Otherwise, the observations completed with 
no further anomalous activity.

    1.2 Completed Three Sets of WF/PC-2 8583 (Imaging Snapshots of Asteroids)

        The WF/PC-2 was used to obtain images of the fifty largest main 
belt asteroids that have favorable apparitions during cycle 9.  The images 
will be searched for companion bodies, as well as mineralogical variegation 
on the resolved main bodies.  There were no reported problems.

    1.3 Completed WF/PC-2 8815 (Cycle 9 Earth Flats)

        The WF/PC-2 was used to monitor flatfield stability.  This proposal 
obtains sequences of Earth streak flats to construct high quality flat 
fields for the WF/PC-2 filter set.  These flat fields will allow mapping of 
the OTA illumination pattern and will be used in conjunction with previous 
internal and external flats to generate new pipeline superflats.  The 
proposal completed nominally.

    1.4 Completed Two Sets of STIS/CCD 8845 (Spectroscopic Flats C9)

        The Space Telescope Imaging Spectrograph (CCD) was used to obtain 
CCD flats in the spectroscopic mode.  The observations completed with no 
reported problems.

    1.5 Completed Two Sets of WF/PC-2 8585 (Cosmological Parameters from 
Type Ia Supernovae at High Redshift)

        The WF/PC-2 was used to measure the cosmological parameters, Omega, 
Lambda, and thus the curvature, Omega_k, using Type Ia supernovae {SNe Ia} 
as calibrated standard candles.  There were no reported problems.

    1.6 Completed Two Sets of WF/PC-2 8780 (Secular Changes in the Jet of M87)

        The WF/PC-2 was used to continue the ongoing investigation of the 
M87 jet that had previously used the FOC.  The investigators will compare 
FOC and WFPC2 images to track secular changes and motions in the jet and 
nucleus.  The observations completed nominally.

    1.7 Completed Five Sets of WF/PC-2 8828 (Cycle 9 Supplemental Darks pt3/3)

        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 re-acquisition failure described in HSTAR 8229 and 2.1, 
occurred during the final iteration of this proposal, and the take data 
flag remained down.  Otherwise, the proposal completed with no further 
reported problems.

    1.8 Completed Two Sets of WF/PC-2 8867 (Gamma-Ray Bursts: Discovering 
The Progenitors And Understanding The Explosion - Visits A0-R0)

        The WF/PC-2 was used to observe a gamma-ray burster, 
GRB000926.  Gamma-ray burst astronomy, one of the most active and exciting 
frontiers in astrophysics, is now entering a critical stage -- with 
dramatic leaps in understanding of these events, as well as new 
discoveries.  Improvements in triggering and positioning accuracy provided 
by the SAX and HETE-2 gamma-ray satellites will allow entirely new classes 
of events to be studied.  Given the recent progress in this field, the 
proposers are now in a position to design precision, broadband measurements 
that can provide quantitative information on the as-yet unknown energy 
sources, the explosion geometry, and the surrounding medium.  In 
particular, the growing evidence of an intimate connection between SNe and 
GRBs can be definitively tested.  The proposal completed with no reported 
problems.

    1.9 Completed WF/PC-2 8677 (Extragalactic Novae: the Maximum Magnitude 
- Rate of Decline Relation in NGC 4472)

        The WF/PC-2 was used to accomplish two goals: {1} to provide the 
first homogeneous observational constraints on theoretical models for novae 
outbursts; and {2} to assess the reliability of novae as standard candles 
by using WFPC2 to collect well sampled light curves for 20-50 novae in the 
supergiant elliptical galaxy NGC 4472, the brightest galaxy within 30 
Mpc.  Both the length of the observing window and the temporal sampling of 
the observations are specifically designed to ensure that the novae peak 
magnitudes and decline rates are measured accurately.  These data will be 
used to construct the first `Maximum Magnitude versus Rate of Decline' 
{MMRD} relation for a galaxy beyond the Local Group.  This relation is not 
only a potentially powerful standard candle, but its shape and dispersion 
are directly linked to physical parameters which govern the physics of 
novae outbursts such as the white dwarf mass, temperature and mass 
accretion rate.  The proposal completed with no reported problems.

    1.10 Completed WF/PC-2 9050 (Outflow Collimation in Bipolar Symbiotic 
Nebulae)

        The WF/PC-2 was used to observe flow collimation in evolved stars 
that is neither expected nor understood.  Classical theories of stellar 
evolution do not predict and cannot explain this bipolarity.  More exotic 
concepts {binary interactions, spun-up atmospheres, poloidal or toroidal 
magnetized winds} have been proposed, but observations are yet to verify or 
falsify any of their predictions.  This proposal will probe the 
near-nuclear morphology and kinematics of four bright, low-extinction 
targets whose large-scale structure is highly bipolar.  The goal is to 
provide a detailed description of the circumnuclear outflows, to uncover 
the physical structure and nature of the collimator, and to evaluate the 
speculative collimation mechanisms.  The bright nucleus has hampered 
efforts to explore the nebular collimators that lie close to the star, so 
we'll use STIS to disperse the nuclear light and, thus, to avoid its 
glare.  A secondary goal is to obtain second-epoch WFPC2 images of all 
targets.  There were no reported problems.

    1.11 Completed WF/PC-2 8599 (A Census of Nuclear Star Clusters in 
Late-Type Spiral Galaxies)

        The WF/PC-2 was used to conduct an I-band snapshot survey of a 
well-defined sample of nearby, face-on spiral galaxies of type Scd or 
later.  The proposal completed nominally.

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The following scheduled proposals were not completed successfully due to 
the STIS safing event:

         Two Sets of STIS/CCD/MA1/MA2 8651 (UV Spectroscopy in the 
Magellanic Bridge: A Typical QSO Absorption Line System?)
         Five Sets of STIS/CCD 8864 (CCD Dark Monitor-Part 2)
         Three Sets of STIS/CCD 8865 (Bias Monitor-Part 2)
         Fifteen Sets of STIS/CCD 9248 (Probing the Large Scale Structure: 
Cosmic Shear Observations)
         Two Sets of STIS/CCD 8262 (Nuclear Kinematics of the Dense Globular
    Cluster M-15)
         STIS/MA1 8572 (Identifying Normal Galaxies at 1.3 < z < 2.5)
         STIS/CCD/MA1 8582 (UV Detectability of Bright Quasars in the Sloan
   Fields)
         STIS/CCD/MA1/MA2 8615 (Ultraviolet Spectroscopy of R Coronae 
Borealis Stars -- Broad Lines from an Accretion Disc?)
         STIS/CCD/MA1 8662 (A Snapshot Survey of the Hot Interstellar Medium)
         STIS/CCD/MA1 8684 (Emission Lines from Photoionized Accretion 
Disks and
   Winds in AGNs)

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2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 22
Successful: 22

  Scheduled Re-acquisitions: 22
Successful: 21

        The re-acquisition at 140/044500Z failed due to a possible star 
problem.  Possibly affected were the proposals detailed in 1.1 and 1.7.

    2.2 FHST Updates:
Scheduled: 54
Successful: 53

        Per HSTAR 8228, the roll delay scheduled for 138/091305Z failed on 
tracker #3.

    2.3 Operations Notes:

        The Space Telescope Imaging Spectrograph remains in safing.

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

        The CCS engineering status limits were adjusted twice per ROP DF-18A.

        ROP NS-3 was utilized at 139/2019Z and at 140/0305Z to dump and 
reset the NSSC-1 status buffer.

        A TTR was written for a required re-transmit at 140/0822Z during a 
486 uplink.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW