HUBBLE SPACE TELESCOPE

                       DAILY REPORT #2431

PERIOD COVERED:  0000Z (UTC) 08/06/99 - 0000Z (UTC) 08/09/99

Daily Status Report as of 221/0000Z

1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:

   1.1 Completed Eight Sets of WF/PC-2 8443 (WF/PC-2 Cycle-8 Supplemental Darks
pt1/3)

       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
observations were completed as planned, and no problems were reported.  

   1.2 Completed Five Sets of STIS/CCD 8408 (STIS CCD Dark Monitor C8)

       The Space Telescope Imaging Spectrograph (CCD) was used to make a CCD
bias calibration observation.  This is to monitor the darks for the STIS CCD. 
The observations were executed as scheduled, and no anomalies were reported.  

   1.3 Completed FGS 8334 (HD 98800: An Opportunity to Measure True Masses for
Low-Mass PMS Stars)

       The Fine Guidance Sensors were used to make astrometric observations of
the low mass pre-main sequence (PMS) star HD98800 in order to measure its true
mass.  HD 98800 became interesting when IRAS found it to have a large infrared
excess, indicating a substantial dust disk.  The observations were executed as
scheduled, and no anomalies were noted.  

   1.4 Completed Three Sets of STIS/CCD 8409 (STIS CCD Bias Monitor C8)

       The Space Telescope Imaging Spectrograph (CCD) was used to make a CCD
bias calibration observation.  This is to monitor the bias in the 1x1, 1x2,
2x1, and 2x2 bin settings at gain=1, and 1x1 at gain = 4, to build up high-S/N
superbiases and to track the evolution of hot columns.  The observations were
executed as scheduled, and no anomalies were reported.  

   1.5 Completed WF/PC-2 6825 (Quantitative Measures of the Evolution of the
Cluster Galaxy Population)

       The WF/PC-2 was used to make observations of galaxy MS1358+64K.  The
goal of this proposal is to understand the differential evolution of cluster
and field galaxies over the redshift range 0.3 < Z < 0.6.  A wave length
calibration image was also taken.  The observations were executed as scheduled,
and no anomalies were noted.  

   1.6 Completed Ten Sets of STIS/CCD 8406 (POMS Test Proposal: STIS
Non-Scripted Parallel Proposal Continuation V)

       The Space Telescope Imaging Spectrograph (CCD) was used to make high
galactic latitude observations taken in parallel with the prime science
observations as part of a POMS proposal.  This is a STIS non-scripted parallel
Condition V proposal.  The observations were completed as scheduled, and no
anomalies were reported.  

   1.7 Completed STIS/CCD 8338 (The Evolution of the Host Galaxies of Powerful
Radio Sources)

       The Space Telescope Imaging Spectrograph (CCD) was used to make
observations of the host galaxy of the powerful radio source known as
MRC1112-23, MRC0349-21, MRC1040-28 and MRC1128-268.  A combined data set of
radio galaxies and quasars will allow powerful tests of the relationship
between radio galaxies and quasars and the evolution of the host galaxies of
powerful radio sources over a wide range of look-back times.  The observations
were executed as scheduled, and no anomalies were noted.  

   1.8 Completed STIS/CCD 7464 (The Evolution of Massive Stars as a Function of
Metallicity: Closing the Loop Observationally)

       The Space Telescope Imaging Spectrograph (CCD) was used to make
observations of the giant OB class star M-31 OB48 which is located in the M-33
galaxy.  The galaxies of the Local Group provide the laboratories for testing
how massive stars evolve as a function of metallicity.  A wavelength
calibration image was also taken.  The observations were executed as scheduled,
and no anomalies were noted.  

   1.9 Completed Five Sets of WF/PC-2 8059 (POMS Test Proposal: WF-2 Targeted
Parallel Archive Proposal)

       The WF/PC-2 was used to make observations in parallel with the prime
science observations.  The parallel opportunities available with WF/PC-2 in the
neighborhood of bright galaxies are treated in a slightly different way from
the normal pure parallels.  Local group galaxies offer the opportunity for a
closer look at young stellar populations.  The observations were completed as
planned, and no anomalies were reported.  

   1.10 Completed STIS/CCD 7438 (Spatially-Resolved Spectroscopy of the UVX in
Elliptical Galaxies)

       The Space Telescope Imaging Spectrograph (CCD) was used to make
spatially resolved far-ultraviolet observations of the large elliptical galaxy
NGC-221.  The prominent far-UV upturn {UVX} in the spectra of elliptical
galaxies originates from stars in their old populations which have evolved
beyond the He-flash at the tip of the red giant branch.  A wavelength image was
also taken.  The observations were completed as scheduled, and no anomalies
were reported.  

   1.11 Completed Three Sets of STIS/CCD 8470 (POMS Test Proposal: STIS
Non-Scripted Parallel Proposal Continuation V)

       The Space Telescope Imaging Spectrograph (CCD) was used to make high
galactic latitude observations taken in parallel with the prime science
observations as part of a POMS proposal.  This is a STIS non-scripted parallel
Condition VI proposal.  The observations were completed as scheduled, and no
anomalies were reported.  

   1.12 Completed STIS/CCD 8313 (Imaging the Host Galaxies of High Redshift
Type Ia Supernovae)

        The Space Telescope Imaging Spectrograph (CCD) was used to make
observations of 971 and its host galaxy.  The propose is to obtain snapshot,
unfiltered STIS images of distant galaxies of known redshift which have hosted
supernovae {SNe} of Type IA found via the Supernova Cosmology Project.  The
observations were completed as scheduled, and no anomalies were reported.  

   1.13 Completed WF/PC-2 8436 (POMS Test Proposal: WFII Backup Parallel
Archive Proposal II)

       The WF/PC-2 was used to make archive observations parallel to the prime
science observations as part of a POMS test proposal.  This is a POMS test
proposal designed to simulate scientific plans.  The observations were
completed as planned, and no anomalies were reported. 

   1.14 Completed STIS/CCD 8202 (Bright Quasar Close Lensing Search)

       The Space Telescope Imaging Spectrograph (CCD) was used to make
observations of HCLQ1301-0 and HCLQ2245-5 as part of a second generation survey
to search for bright lensing quasars.  With the restored PSF, new images will
be considerably more sensitive to the presence of both close separation and
faint lens components, and because STIS reaches two magnitudes fainter the PC,
the new snapshot images will have much greater dynamic range.  The observations
were executed as scheduled, and no anomalies were noted.  

   1.15 Completed WF/PC-2 6488 (An Ultra-Faint Galaxy Count and Redshift Survey
Using Cluster Lenses)

       The WF/PC-2 was used to make observations of distant ultra-faint
galaxies using the forground galactic cluster Abell-2219 as a gravitational
lens cluster.  The abundance, clustering and other properties of such sources
would be valuable constraints on theories of structure formation.  The
observations were executed as scheduled, and no anomalies were noted.  

   1.16 Completed STIS/MA2 8225 (Absorption and Obscuration in Radio-Loud
Quasars)

       The Space Telescope Imaging Spectrograph (MA2) was used to make
observations of the radio-loud quasar MRC2255-28.  The role of associated
absorption systems and dust obscuration close to the central engines of AGN is
not understood.  The observations were completed as planned, and no anomalies
were reported.   

   1.17 Completed Six 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.  

   1.18 Completed WF/PC-2/STIS/CCD 8169 (HST-Galileo Io Campaign)

       Both the WF/PC-2 and the Space Telescope Imaging Spectrograph (CCD) were
used to make observations of Jupiter’s moon Io.  Io plays a central role in the
Jovian system, yet the mechanisms that couple its volcanoes, the tenuous
atmosphere, the escaping corona and the plasma torus remain elusive.  In 1999
there is the unique opportunity to combine HST observations with the Galileo
close flybys of Io.  The observations were completed as planned, and no
problems were reported.  

   1.19 Completed STIS/CCD/MA1 8043 (Physical Properties of H-I and H-II
Regions)

       The Space Telescope Imaging Spectrograph (CCD and MA1) was used to make
observations of the early-type star HD2827 in order to study its 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.  

   1.20 Completed STIS/CCD/MA1 7481 (The Wind-momentum Luminosity Relationship
for M31 and M33 B-supergiants)

       The Space Telescope Imaging Spectrograph (CCD and MA1) was used to make
observations of the B class supergiant stars M-33 110-A and M-31 and OB8-17
which are locate in the M-31 galaxy.  The purpose of these observations is to 
acquire STIS low-resolution ultraviolet spectra of early B-supergiants in
galaxies M31 and M33 to determine the terminal velocities of their stellar
winds.  The observations were completed as planned, and no anomalies were
reported.  

   1.21 Completed WF/PC-2 7339 (Sizes and Structures of Faint Blue Compact
Galaxies that are New Candidates for Proto-Spheroidal Galaxies)

       The WF/PC-2 was used to obtain two-band WFPC-2 images of a unique sample
of the faint blue compact galaxy SA57-5558 at redshift of z ~ 0.7, that is
excellent new candidate for being spheroidal galaxies, caught in the act of
undergoing a major star-forming event.  The observations completed with no
reported anomalies.

   1.22 Completed WF/PC-2 8221 (The Next Bright Galactic Nova: High Resolution
Imaging)

       The WF/PC-2 was used to make observations of Nova Velor (a.k.a., T
Pyxidis).  The recurrent nova T Pyxidis is one of only ~20 novae with known
shells, and the only recurrent nova with clearly resolved circumstellar
matter.  The observations were completed as planned, and no anomalies were
reported.  

   1.23 Completed WF/PC-2 6701 (Photometry of the Globular Cluster System of
the Sagittarius Dwarf Galaxy)

       The WF/PC-2 was used to make observations of the globular cluster system
Ter8 which is located the Sagittarius Dwarf Galaxy.  Isochrone fits to these
data will yield the accurate age of this system.  The observations were
completed as scheduled, and no anomalies were reported. 

   1.24 Completed STIS/CCD/MA1 8171 (HST Far-UV Imaging and Spectra of
Jupiter's Aurora During the Galileo Extended Mission)

       The Space Telescope Imaging Spectrograph (CCD and MA1) was used to make
far-ultraviolet spectrographic observations of the aurora on the planet Jupiter
as part of the extended Galileo Mission.  Observations were also made of the
moon Europa.  This is to study the nature of the satellite auroral footprints
in Jupiter's atmosphere.  The observations were completed as planned, and no
problems were reported.  

   1.25 Completed Three Sets of FGS 8335 (Calibrating Stellar Models with the
Pleiades: Resolving the Distance Discrepancy)

       The Fine Guidance Sensors were used to make astrometric observations of
the stars H186, H1101 and H1286 that are located in the Pleiades cluster.  This
is the first phase of a multi-year effort to measure true masses for low-mass
dwarfs in the Pleiades and to determine an accurate distance to this
fundamental cluster.  The observations were completed as scheduled, and no
anomalies were noted.  

2.0 FLIGHT OPERATIONS SUMMARY:

   2.1 Guide Star Acquisitions: 

                            Scheduled Acquisitions : 26
                                        Successful : 26

                          Scheduled Reacquisitions : 20
                                        Successful : 20

   2.2 FHST Updates: 

                              Scheduled : 65
                             Successful : 63

       The updates scheduled for 220/001907Z and 221/061009Z failed.

   2.3 Operations Notes: 

       HSTAR 7211 was written for four anomalous guide star separations: during
the acquisition at 211/1203Z, and during re-acquisitions at 211/1303Z,
211/1341Z, and 211/1440Z.  In each case, the acquisition/re-acquisition was
successful.  Speculation is that these larger than normal separations could be
caused by either a double star or FGS confusion due  to Orion Nebula emission.

       A TTR was written for an NCC system problem at 218/161716Z.  Another TTR
was written for an engineering data dropout from 221/023609Z until 221/023626Z.

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

       The NSSC-1 status buffer was dumped at 219/0018Z per ROP NS-3.

       The STIS MCE-1 reset twice: at 219/012011Z and at 219/020100Z.  In each
case, the low voltage was on.  In the first case, the vehicle was in an SAA
interval; in the second, not.  Per ROP NS-12, the STIS flight software error
counter was reset twice.  MAMA-1 was recovered via normal SMS commanding at
219/1720Z.

       As described in HSTAR 7212, the battery 6 recharge ratio flagged
out-of-limits low for one orbit at 220/215205Z and at 220/233014Z, with a value
each time of 1.26 (the limit is 1.25 for orbits with sun times of less than 64
minutes -- the present sun time is approximately 61 minutes).  Though limits
were not broken, all other battery recharge ratios were higher than usual.

       HST operations transferred to the SAMS backup facility at 221/0754Z to
make room for Joint Integrated Simulation #4 (Planning/EVA-3) which will begin
late this afternoon.

3.0 SIGNIFICANT FORTHCOMING EVENTS: 

       Continuation of normal science observations and calibrations.

/DMH