HUBBLE SPACE TELESCOPE

   DAILY REPORT #2884

PERIOD COVERED:  0000Z (UTC) 05/31/01 - 0000Z (UTC) 06/01/01

Daily Status Report as of 152/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Two Sets of WF/PC-2 8682 (A Snapshot Study of 
0bservational Cosmology)

        The WF/PC-2 was used to examine the observational constraints on 
the cosmic star formation history that is currently among the most active 
fields in observational cosmology.  The most widely used tracer of the 
co-moving volume-averaged star formation rate {SFR} is the UV luminosity 
density, which early results found to peak at z~1- 2.  The apparent 
identification of the primary epoch of metal production and star formation 
in the Universe led to intense theoretical and observational 
interest.  Nevertheless, and remarkably for such a fundamental observation, 
little is known about the history of star formation in the Universe beyond 
its global average.  There were no reported anomalies.

    1.2 Completed Two Sets of 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.

    1.3 Completed 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 proposal completed with no reported problems.

    1.4 Completed Two Sets of WF/PC-2 8602 (A Snapshot Survey of the Sites 
of Recent, Nearby Supernovae)

        The WF/PC-2 was used to conduct a snapshot survey in V and I of the 
sites of the nearby SNe, which have precisely known positions, to obtain 
high-resolution information on their local environment.  The proposal 
completed with no reported problems.

    1.5 Completed WF/PC-2 8581 (A Search For Low-Mass Companions To 
Ultracool Dwarfs)

        The WF/PC-2 was used to search for very low-mass {VLM} companions 
to a complete sample of 120 late-M and L dwarfs, drawn mainly from the 
2MASS and SDSS surveys.  The primary goal is to determine the multiplicity 
of M < 0.1 M_odot dwarfs.  In particular, we aim to identify binary systems 
suitable for long-term astrometric monitoring and mass measurement, and 
systems with cool, sub-1000K companions.  The proposal completed with no 
reported problems.

    1.6 Completed WF/PC-2 8592 (Pixel Microlensing of M87)

        The WF/PC-2 was used to undertake a pixel microlensing study of M87 
in order to: 1} probe the lower end of the M87 IMF via star-star lensing, 
2} possibly obtain the first evidence of Massive Compact Objects (MACHOs) 
in the halo of a galaxy other than our own, and 3} search for intracluster 
MACHOs.  The proposal completed nominally.

    1.7 Completed Three Sets of WF/PC-2 9133 (Imaging of Gravitational Lenses)

        The WF/PC-2 was used to observe gravitational lenses that offer 
unique opportunities to study cosmology, galactic structure, galaxy 
evolution, quasar hosts and extinction.  They are also the only sample of 
galaxies selected on the basis of their mass rather than their luminosity 
or surface brightness.  While gravitational lenses can be discovered with 
ground-based optical and radio observatories, converting them from 
curiosities into scientific tools requires HST.  As described in 
yesterday's report and HSTAR 8329, the acquisition for the first iteration 
of this proposal defaulted to fine lock backup on one FGS only, possibly 
affecting seven observations.  Otherwise, there were no other reported 
anomalies.

    1.8 Completed Five Sets of WF/PC-2 8816 (Cycle 9 UV Earthflats)

        The WF/PC-2 was used to obtain sequences of Earth streak flats to 
improve the quality of pipeline flat fields for the WFPC2 UV filter set and 
in order to monitor flat field stability.  There were no reported problems.

    1.9 Completed Two Sets of WF/PC-2 9132 (Resolving the Puzzling Dark 
Mass Concentration in Abell 1942)

        The WF/PC-2 was used to make observations that will significantly 
improve the precision and localized position of a puzzling 
signal.  Independent lensing analyses of two optical datasets reveal a 
striking mass concentration south of the cluster center with no obvious 
visible source counterpart.  Placed at the redshift of the cluster the 
implied mass would be M{0.5h^-1mboxMpc} >= 1* 10^14M_odot.  The absence of 
an obvious excess of faint sources in suitably deep infrared images makes 
it highly unlikely that such a strong lensing signal can be caused by a 
projected background cluster of galaxies.  No anomalous activity was reported.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 11
Successful: 11

  Scheduled Re-acquisitions:  5
Successful:  5

    2.2 FHST Updates:
Scheduled: 24
Successful: 24

    2.3 Operations Notes:

        The Space Telescope Imaging Spectrograph (STIS) remains in sage mode.

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

        The CCS 486 engineering status buffer limits were adjusted twice 
per ROP DF-18A.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW