HUBBLE SPACE TELESCOPE

                       DAILY REPORT #2356

PERIOD COVERED:  0000Z (UTC) 04/21/99 - 0000Z (UTC) 04/22/99

Daily Status Report as of 112/0000Z

1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:

   1.1 Completed Two Sets of STIS/CCD/MA1/MA2 8043 (Physical Properties of
H-I and H-II Regions)

       The Space Telescope Imaging Spectrograph (CCD, MA1 and MA2) was used
to make observations of the early-type stars HD210839 and HD94493 in order
to study their H-I and H-II regions.  Interstellar absorption lines within
the wavelength intervals 1170-1370A and 1630-1890A in the spectra of 10
early-type stars are being observed with the highest resolution mode of
STIS.  A wavelength calibration image was also taken.  The observations
were executed as scheduled, and no anomalies were noted.

   1.2 Completed STIS/CCD 7949 (CCD Dark and Bias Monitor -- Cont. to June 99)

       The Space Telescope Imaging Spectrograph (CCD) was used to conduct a
CCD dark calibration and a bias monitoring program.  It was also scheduled
to 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.

   1.3 Completed Three Sets of WF/PC-2 7713 (WF/P-2 Cycle 7 Supplemental
Darks pt3/3)

       The WF/PC-2 was used to make supplemental dark calibration images.
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 completed as planned, and no anomalies were noted.

   1.4 Completed WF/PC-2 7434 (The Supernova Intensive Study)

       The WF/PC-2 was used to continue the long-term project on supernovae
by observing SN1987A.  HST can make unique contributions to understanding
supernovae, as has been demonstrated through this program in past years,
and now STIS and NICMOS offer new opportunities for deepening this
investigation.  The aim of the proposal is to explore the UV emission from
supernovae, exploit the spatial resolution of HST and press the late-time
observations of supernovae into uncharted territory.  The observations were
completed as planned, and no anomalies were reported.

   1.5 Completed Two Sets of STIS/CCD 7912 (STIS Parallel Archive Proposal
- Nearby Galaxies - Imaging and Spectroscopy)

       The Space Telescope Imaging Spectrograph (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.

   1.6 Completed WF/PC-2 7619 (WF/PC-2 Cycle 7 Decontamination)

       The WF/PC-2 was used to conduct a Cycle 7 decontamination procedure.
Ultraviolet-blocking contaminants were removed, and hot pixels cured, by
warming the CCDs to +20C for 6 hours.  A variety of internal images were
taken before and after the decontamination in order to verify its success
and to monitor the instrument health.  The procedures were conducted as
scheduled, and no problems were reported.

   1.7 Completed STIS/CCD 8393 (POMS Test Proposal: STIS Non-Scripted
Parallel Proposal Continuation IV)

       The Space Telescope Imaging Spectrograph (CCD) was used to make
POMS, non-scripted, low galactic latitude observations made in parallel
with the prime science observations.  The observations were executed as
scheduled, and no anomalies were noted.

   1.8 Completed WF/PC-2 6357 (The Nuclear Morphology of Elliptical Galaxies)

       The WF/PC-2 was used to make images of the early type, large,
elliptical galaxy ESO437-15 (taken from a list of 150 galaxies) in order to
study its nuclear morphology.  This survey will complement Illingworth's
snapshot study of later Hubble types.  The observations were completed as
scheduled, and no anomalies were reported.

   1.9 Completed STIS/CCD 8091 (POMS Test Proposal: STIS Non-Scripted
Parallel Proposal Continuation)

       The Space Telescope Imaging Spectrograph (CCD) was used to make high
galactic latitude, non-scripted, parallel observations.  The observations
were completed as planned, and no anomalies were noted.

   1.10 Completed STIS/CCD 7403 (Measuring Black Hole Masses in Broad-Lined
AGNs)

       The Space Telescope Imaging Spectrograph (CCD) was used to make
observations of broad-lined active galactic nuclei (AGN) located in  galaxy
NGC-4579.  Broad emission lines in AGNs are considered one of the most
direct signatures of a large central mass, which is presumed to be a black
hole.  A wavelength calibration image was also taken.  The observations
were completed as planned, and no anomalies were reported.

   1.11 Completed WF/PC-2 7623 (WF/PC-2 Cycle 7 Internal Flats)

       The WF/PC-2 was used to make a set of internal Cycle 7 calibration
flats which are designed to monitor the pixel to pixel flat field response
and the visflat lamp degradation, as well as detect any possible changes
due to contamination.  The calibration observations were completed as
planned, and no problems were reported.

   1.12 Completed Three Sets of WF/PC-2 8090 (POMS Test Proposal: WF-II
Parallel Archive Proposal Continuation)

       The WF/PC-2 was used in the parallel mode to make some low galactic
latitude archive observations.  The program will be used to take parallel
images of random areas of the sky.  The observations were executed as
scheduled, and no anomalies were noted.

   1.13 Completed WF/PC-2 8053 (WF/PC-2 Cycle-7 Earth Flats -- Part II)

      The WF/PC-2 was used to take Earth flat calibration images.  This
proposal obtains sequences of Earth streak flats to construct high quality
flat fields for the WF/PC-2 filter set.  The observations were executed as
scheduled, and no anomalies were noted.

   1.14 Completed Three Sets of STIS/MA1 7950 (Cycle 7 MAMA Dark Measurements)

       The Space Telescope Imaging Spectrograph (MA1) was used to make a
dark calibration image.  This is to establish if the detectors are
performing nominally, that no internal movement of the MCP has taken place,
and establish dark level in orbit for a given operating temperature.  These
darks will be used in later image reduction and also trended over
instrument life time as indicators of detector degradation or damage.  The
observations were completed as planned, and no problems were reported.

   1.15 Completed STIS/CCD 7936 (External to Internal Wavelength Correction
Calibration)

       The Space Telescope Imaging Spectrograph (CCD) was used to conduct
an external to internal wavelength correction calibration.  This will
quantitatively characterize the degree, if any, of the offset of the
wavelength system for an external source from that determined by the
internal wavelength calibration system.  The calibration was executed as
scheduled, and no anomalies were reported.

   1.16 Completed WF/PC-2/STIS/CCD 7615 (Determination of the Mass Function
of a Globular Cluster Through Gravitational Microlensing)

       The WF/PC-2 and the Space Telescope Imaging Spectrograph (CCD) were
used to make gravitational microlensing observations of the large globular
cluster NGC-6656 located in Sagittarius in order to study its mass
function.  Gravitational microlensing offers a unique and direct method of
determining the masses of stars and other compact objects down to planetary
masses.  A bias and dark calibration observations were also taken.  The
observations were completed as planned, and no problems were reported.

2.0 FLIGHT OPERATIONS SUMMARY

   2.1 Guide Star Acquisitions:

                            Scheduled Acquisitions : 6
                                        Successful : 6

                          Scheduled Reacquisitions : 9
                                        Successful : 9

   2.2 FHST Updates:

                              Scheduled : 17
                             Successful : 17

   2.3 Operations Notes:

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

       At 111/1113Z, the NICMOS FPA temperature sensor was enabled for
Detector 2.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

       Continuation of normal science observations and calibrations.

/DMH