HUBBLE SPACE TELESCOPE

   DAILY REPORT #2901

PERIOD COVERED:  0000Z (UTC) 06/25/01 - 0000Z (UTC) 06/26/01

Daily Status Report as of 177/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Three 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 Two Sets of 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.

    1.3 Completed Six Sets of WF/PC-2 8935 (Cycle 10 Standard Darks)

        The WF/PC-2 was used to obtain dark frames every week in order to 
provide data for the ongoing calibration of the CCD dark current rate, and 
to monitor and characterize the evolution of hot pixels.  Over an extended 
period these data will also provide a monitor of radiation damage to the 
CCDs.  The proposal completed with no reported problems.

    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 8812 (Cycle 9 Internal Monitor)

        The WF/PC-2 was used to obtain routine internal monitors for WFPC2 
in order to monitor the health of the cameras.  A variety of internal 
exposures are obtained in order to provide a monitor of the integrity of 
the CCD camera electronics in both bays {gain 7 and gain 15}, a test for 
quantum efficiency in the CCDs, and a monitor for possible buildup of 
contaminants on the CCD windows.  There were no reported problems.

    1.6 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.

    1.7 Completed FGS/1 8731 (A High Angular Resolution Survey of the Most 
Massive Stars in the SMC)

        Fine Guidance Sensor #1 was used to conduct high angular resolution 
observations of some of the SMC's hottest and most luminous objects by 
conducting a comprehensive survey of nearly every spectral type in the 
upper portion of the HR diagram.  Binary or multiple star systems will be 
detected down to an unprecedented level, more than one order of magnitude 
better than possible with WFPC2.  The targets selected include a 
representative list of normal Main Sequence O-stars and their evolved 
descendents, namely supergiants, hypergiants, LBVs, and WRs, many of which 
have been previously observed by HST's spectrometers for purposes of 
cosmological calibrations.  The observations completed, and no problems 
were reported.

    1.8 Completed WF/PC-2 8597 (The Fueling of Active Nuclei: Why are 
Active Galaxies Active?)

        The WF/PC-2 was used to investigate the accretion onto massive 
black holes that are believed to be the energy source for AGN.  However, 
evidence for black holes in quiescent galaxies has also been reported.  Why 
are these galaxies inactive?  One possibility is that active galaxies are 
better at providing fuel to the nuclear region than quiescent 
galaxies.  Other possible fueling mechanisms such as ``bars-within-bars'' 
or nuclear spirals cannot be investigated from the ground because they are 
relatively small features in the ISM.  The observations were completed as 
planned.

    1.9 Completed Two Sets of WF/PC-2 8634 (Atmospheric Variability on 
Uranus and Neptune)

        The WF/PC-2 was used to obtain snapshot observations of Uranus and 
Neptune to monitor changes in their atmospheres on time scales of months to 
years.  Uranus is rapidly approaching equinox in 2007, with another 4 
degrees of latitude in the northern hemisphere becoming visible every 
year.  Recent HST images during this unique epoch have revealed: {i} 
strongly wavelength-dependent latitudinal structure, {ii} the presence of 
numerous visible-wavelength cloud features in the northern hemisphere, and, 
{iii} in the near-IR, discrete features northward of 25degrees N that have 
the highest contrast ever seen for a Uranian cloud.  Long-term ground- 
based observations show seasonal brightness changes whose origins are not 
well understood.  Recent IR images of Neptune obtained using adaptive 
optics on the Keck Telescope indicate that a new "Bright Companion" type of 
feature has recently appeared in the southern hemisphere.  Snapshot 
observations of these two dynamic planets can supply context in which to 
discern the nature of long-term changes in their latitudinal atmospheric 
bands and to track the appearance, movement, and disappearance of discrete 
albedo features.  There were no reported problems.

    1.10 Completed 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.

    1.11 Completed Two Sets of WF/PC-2 8345 (Multipolar Bubbles and Jets in 
Very Low Excitation Planetary Nebulae - A WF/PC-2 H-Alpha Imaging Survey)

        The WF/PC-2 was used to make H-Alpha observations of the very low 
excitation planetary nebula PK013-04D1 in order to study its multipolar 
bubbles and jets.  Comparison of the morphology of this young PNe sample 
with more evolved PNe populations will set new constraints on models for 
the production of jet-like outflows and nebular evolution.  The 
observations were completed as planned, and no problems were reported.

    1.12 Completed WF/PC-2 8192 (A Snapshot Survey of Probable Nearby Galaxies)

        The WF/PC-2 was used to make a snapshot survey images of a probable 
nearby galaxy KK035.  The census of galaxies in the Local Volume of space 
is very incomplete, particularly at the faint end.  The observations were 
executed as scheduled, and no anomalies were noted.

    1.13 Completed WF/PC-2 8230 (Snapshot Survey of Dynamically Close 
Galaxy Pairs from z=0.1 to z=0.5)

        The WF/PC-2 was used to make snapshot survey observations of 
galactic cluster Gal-Clus-0.  This is to obtain snapshot images of a large, 
well-defined, and dynamically selected sample of close galaxy pairs at 
moderate redshift.  The observations were executed as scheduled, and no 
anomalies were noted.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 14
Successful: 14

  Scheduled Re-acquisitions:  3
Successful:  3

    2.2 FHST Updates:
Scheduled: 33
Successful: 31

        HSTAR 8249 details FHST full maneuver update failures at 
177/040039Z and at 177/040324Z due to failed error box results for both 
trackers 2 and 3.  However, the subsequent acquisition was successful.

    2.3 Operations Notes:

        The STIS instrument remains in safe mode.

        The SSR EDAC error counter was cleared twice, using ROP SR-1A.

        The engineering status buffer limits were adjusted twice as 
directed by ROP DF-18A.

        Per ROP DF-07A, the ephemeris table was loaded at 177/0035Z.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW