HUBBLE SPACE TELESCOPE

                       DAILY REPORT #2138

PERIOD COVERED:  0000Z (UTC) 06/04/98 - 0000Z (UTC) 06/05/98

Daily Status Report as of 156/0000Z

1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:

   1.1 Completed NIC/3 7830 (IR Spectra for Known-Mass M Dwarfs)

       The Near Infrared Camera (Camera Three) was used to make infrared
spectrographic observations of M-Class dwarf star GJ748AB.  Over the last
decade there has been considerable debate on two major issues in the
low-mass star literature: {1} the effective temperature scale for M dwarfs
and its relation to mass and luminosity and {2} the conversion from an
absolute magnitude in some passband to a bolometric magnitude.  The
observations were executed as scheduled, and no anomalies were noted.

   1.2 Completed WF/PC-2 7712 (WF/PC-2 Cycle 7 Supplemental Darks pt2/3)

       The WF/PC-2 was used to make a series of Cycle 7 supplemental
calibration darks.  This dark calibration program obtains three dark frames
every day to provide data for monitoring and characterizing the evolution
of hot pixels.  The observations were executed as scheduled, and no
anomalies were noted.

   1.3 Completed WF/PC-2 7622 (WF/PC-2 Cycle 7 Internal Monitor)

       The WF/PC-2 was used to make a set of Cycle 7 internal monitoring
calibration measurements.  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.  A bias calibration and an internal flat calibration image were
also taken.  The observations were executed as scheduled, and no anomalies
were noted.

   1.4 Completed Three Sets of WF/PC-2 7620 (WF/PC-2 Cycle 7 Standard Darks)

       The WF/PC-2 was used to make a series of Cycle 7 standard dark
calibration images.  This dark calibration program obtains 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.  The observations were executed as scheduled, and no anomalies were
noted.

   1.5 Completed NIC/1/2/3 7901 (NICMOS Post-Campaign Focus
Monitoring)

       The Near Infrared Camera (Cameras One, Two and Three) was used to
make some post-campaign focus monitoring observations by using star cluster
NGC-3603.  This proposal is used to determine and monitor the optimal focus
and tilt settings for all three NICMOS cameras after the first NIC/3
observing campaign.  The observations were executed as scheduled, and no
anomalies were noted.

   1.6 Completed STIS/CCD 7926 (CCD Dark and Bias Monitor -- Continued)

       The Space Telescope Imaging Spectrograph (CCD) was used to make
several dark and bias calibration observations.  This is to measure CCD
dark current and bias rates for the two supported amplifier settings {gain
= 1 and gain = 4} in order to gather data for making superdarks and
superbiases.  These observations will also track the growth of hot pixels
on the CCD in general and within the various target acquisition apertures
specifically.  The observations were executed as scheduled, and no
anomalies were noted.

   1.7 Completed STIS/MA2 7604 (Cycle 7 MAMA Dark Measurements)

       The Space Telescope Imaging Spectrograph (MA2) was used to make MAMA
dark measurements.  These darks will be used in later image reductions and
also trended over the instrument's life time as an indicator of the
detector's degradation or damage.  The observations were completed as
scheduled, and no problems were reported.

   1.8 Completed NIC/1/2/3 7871 (The Properties of High Redshift Galaxies :
A Near-Infrared Redshift Survey)

       The Near Infrared Camera (Cameras One, Two and Three) was used to
make infrared galactic survey observations of high redshifted galaxies in s
sky field designated as Field-1417.  A comparison between the population of
galaxies in the low {z<1} and high {z>2} redshift universe has shown that
the peak era of star forming activity in the universe occurs in the
redshift interval 1<z<2.  Approximately one hour of this four hour proposal
was affected by the guide star acquisition failure (at 155/0757Z) described
in yesterday's report and in HSTAR 6503.  The take data flag remained down
until a successful re-acquisition (at 155/0905Z) following an ARU/PRT
uplink.  One observation was affected.  Otherwise, the observations were
executed as scheduled, and no further anomalies were noted.

   1.9 Completed Three Sets of STIS/CCD 7908 (POMS Test Proposal: STIS
Non-Scripted Parallel Proposal)

       The Space Telescope Imaging Spectrograph (CCD) was used to make
calibration observations as part of the POMS Test Proposal.  This was a
STIS non-scripted parallel proposal.  The first iteration of this proposal,
containing four observations, was affected.  Otherwise, the observations
were completed as planned, and no further problems were reported.

   1.10 Completed NIC/1/2/3 7474 (Searching for Low Mass Stars: the Mass
Function at the Hydrogen Burning Limit)

       The Near Infrared Camera (Cameras One, Two, and Three) was used to
use the unprecedented IR imaging capabilities of NICMOS to study the
low-mass stars at the end of the main sequence the nearby globular cluster
NGC-5139 which spans a wide range of metallicity, precisely at the
wavelength corresponding to its maximum emission. These observations would
complete our ongoing investigation by making it possible, for the first
time, to reliably count stars right down to and beyond the main sequence
H-burning limit, thus leaving no doubt as to whether the IMF indeed drops
there or starts rising once again close to the limit.  The observation
completed as planned with no problems.

   1.11 Completed STIS/CCD 7911 (STIS Galactic Plane Pure Parallel Program)

       The Space Telescope Imaging Spectrograph (CCD) was used to make low
galactic latitude survey observations in parallel with the prime science
observations.  Short exposures with the 50CCD imaging mode will provide the
wavelength zero-point calibration.  These data will be placed immediately
into the Hubble Data Archive.  The observations were executed as scheduled,
and no anomalies were noted.

   1.12 Completed Two Sets of NIC/3 7919 (NICMOS Camera 3 Campaign Snapshots)

       The Near Infrared Camera (Camera Three) was used to make images of
galaxies NGC-3627, NGC-5055, NGC 3593 and NGC 2403 as part of the NICMOS
Camera 3 campaign snapshots.  The proposal is to obtain wide field snapshot
images of nearby galaxies in Paschen Alpha which is inaccessible from the
ground.  The observations were executed as planned, and no anomalies were
reported.

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

       The Near Infrared Camera (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.

2.0 FLIGHT OPERATIONS SUMMARY:

   2.1 Guide Star Acquisitions:

                            Scheduled Acquisitions : 10

                                        Successful : 9
       The acquisition at 156/011121Z failed to RGA control when the search
radius limit was exceeded on FGS-1.  Fine lock had been achieved on FGS-2,
but there were notably large values for the V1 calculated FGS attitude
error angle.  HSTAR 6508 documents this event.  An approximate
one-half-hour iteration of STIS proposal 7919 (NICMOS Camera Three Campaign
Snapshot), containing one observation, occurring during the period of the
next report, was affected.

                          Scheduled Reacquisitions : 6
                                        Successful : 6

   2.2 FHST Updates:

                              Scheduled : 23
                             Successful : 20

       As detailed in HSTAR 6506, the update at 155/115452Z using FHST-1
and FHST-3 failed.  The following full maneuver updates and the acquisition
were successful.

       The update at 156/004046Z failed due to no FHST-1 data when the HST
entered a ZOE.  The report notes that there should have been adequate data
prior to the ZOE.  HSTAR 6510 was written.  The following acquisition
failed.

       The update at 156/0934Z failed when stars where not seen in FHST-2.
HSTAR 6509 was written.

   2.3 Operations Notes:

       As reported in HSTAR 6505, during an SSR1 science dump at
155/120830Z, 132 correctable EDAC error counts were encountered in a new
place, between 13100 and 14780.

       The SSR EDAC error counter was cleared seven times using ROP SR-1.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

       Continuation of normal science observations and calibrations, and
the second NICMOS Camera Three Campaign.
/DMH