HUBBLE SPACE TELESCOPE

   DAILY REPORT #2899

PERIOD COVERED:  0000Z (UTC) 06/21/01 - 0000Z (UTC) 06/22/01

Daily Status Report as of 173/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Two 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 proposal completed with no reported problems.

    1.2 Completed WF/PC-2 8177 (Investigating Type Ia Supernovae and an 
Accelerating Universe)

        The WF/PC-2 was used to obtain rest frame U and B photometry for 
four z~ 0.85 Supernova (SN) Ia.  These observations will be coupled to 
ground-based rest frame V photometry and spectra.  These data, combined 
with previous samples, will extend the D_L vs. z diagram for SN Ia to 
z~0.85, and allow us to discriminate the redshift dependence of supernova 
magnitudes in an accelerating Universe from that expected to result from 
systematic effects such as age of the stellar population, chemical 
evolution, a drift in the properties of dust, and weak gravitational 
lensing.  The proposal completed with no reported problems.

    1.3 Completed 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.  There were no reported 
anomalies.

    1.4 Completed WF/PC-2 9086 (Investigating the Formation History of 
Spiral Galaxy Halos)

        The WF/PC-2 was used to make observations in order to constrain the 
origin of spiral galaxy halos by studying stellar populations near the tip 
of the red giant branch.  This will be the first systematic study of this 
population in external galaxies and will quadruple the sample of normal 
spiral galaxies for which the halo metallicity distribution function is 
measured.  This larger sample will permit study of the relationship between 
the bulge, disk, and halo components and between halos and globular 
systems.  Such correlations will in turn provide indications as to whether 
the halo, bulge, and globular cluster systems built up nearly 
simultaneously in the early universe or were accreted over time through 
different kinds of merging events.  The proposal completed nominally.

    1.5 Completed WF/PC-2 8820 (Wavelength Stability of Narrow Band and 
Linear Ramp Filters)

        The WF/PC-2 was used to verify the mapping of wavelength as a 
function of CCD position on linear ramp filters and to check for changes in 
central wavelengths of the narrow band filters.  The proposal completed 
nominally.

    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.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions:  4
Successful:  4

  Scheduled Re-acquisitions: 11
Successful: 11

    2.2 FHST Updates:
Scheduled: 10
Successful: 10

    2.3 Operations Notes:

        The STIS instrument remains in safe mode.

        HSTAR 8247 was written when CCS "G" string experienced fatal errors 
on pipeline archive jobs at 172/1551Z.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW