HUBBLE SPACE TELESCOPE

                       DAILY REPORT #2439

PERIOD COVERED:  0000Z (UTC) 08/18/99 - 0000Z (UTC) 08/19/99

Daily Status Report as of 231/0000Z

1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:

   1.1 Completed Four Sets of STIS/CCD 8202 (Bright Quasar Close Lensing
Search)

       The Space Telescope Imaging Spectrograph (CCD) was used to make
observations of HCLQ2358-4, HCLQ2318-0, HCLQ0243-0 and HCLQ0153-4 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.  

   1.2 Completed Two 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 WF/PC-2 8181 (Resolving Sirius-like Binaries)

       The WF/PC-2 was used to make observations of the star HD18313 in order
to try and resolve these Sirius-like binary star systems.  Subsequent
determinations of the visual orbits of the resolved binaries with the HST will
provide dynamical measurements of the white-dwarf masses.  The observations
were completed as scheduled, and no anomalies were reported.  

   1.4 Completed 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/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 an eclipse 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.  

   1.6 Completed WF/PC-2 8301 (A Snapshot Survey of X-ray Selected Central
Cluster Galaxies)

       The WF/PC-2 was used to make snapshot survey observations of the x-ray,
central cluster galaxy Z235.  Central cluster galaxies are the most massive
stellar systems known and have been used as standard candles for many decades. 
The observations were executed as scheduled, and no anomalies were noted. 

   1.7 Completed WF/PC-2 8020 (Tracking the UV Upturn to z=0.55)

       The WF/PC-2 was used to make ultraviolet observations of galactic
cluster CL0016+16.  The high concentration of elliptical galaxies in this
cluster, when combined with its large distance, allows the observation of 10
ellipticals in the relatively small field-of-view.  The STIS MCE-1 reset
described in 2.3 occurred about halfway through this eight-and-one-half hour
proposal, possibly affecting one or more of the observations.  Otherwise, the
observations were completed as planned, and no further problems were reported.

   1.8 Completed STIS/CCD 8172 (STIS Deep DLA Imaging Survey II)

       The Space Telescope Imaging Spectrograph (CCD) was used to make deep
observations of quasar/alpha galaxy PKS0528-25.  The HST imaging, together with
ground-based spectroscopy, will unify absorption-line studies and faint galaxy
imaging studies, providing a comprehensive picture of the history of assembly,
star formation, gas consumption, and chemical enrichment in the Damped
Lyman-Alpha galaxies.  The observations were executed as scheduled, and no
anomalies were noted.  

   1.9 Completed 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.  

   1.10 Completed WF/PC-2 7495 (Survey of Gravitational Lenses as Cosmological
Tools)

       The WF/PC-2 was used to make survey observations of object MG414+053 by
obtaining deep, high-resolution images in the optical and near IR in order to
see if it is gravitationally lensed and could be used as a cosmological tool. 
The observations were executed as scheduled, and no anomalies were noted.  

   1.11 Completed Two 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.  

   1.12 Completed STIS/CCD 8080 (STIS Spectroscopic CCD Flatfielding --
Revised)

       The Space Telescope Imaging Spectrograph (CCD) was used to make CCD flat
fielding calibration observations in the spectroscopic mode.  The observations
were completed as planned, and no anomalies were reported.   

   1.13 Completed WF/PC-2 7337 (The Central Mass Profile in the Lowest Redshift
Cluster Lenses)

       The WF/PC-2 was used to make observations of the X-ray luminous cluster
of galaxies around the radio source Abell478.  This cluster produces the
brightest gravitational arc known.  The observations were executed as
scheduled, and no anomalies were noted.  

2.0 FLIGHT OPERATIONS SUMMARY:

   2.1 Guide Star Acquisitions: 

                            Scheduled Acquisitions: 7
                                        Successful: 7

                         Scheduled Re-acquisitions: 7
                                        Successful: 7

   2.2 FHST Updates: 

                              Scheduled: 17
                             Successful: 17

   2.3 Operations Notes: 

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

       The NICMOS FPA temperature sensor for detector 3 was enabled at
230/0959Z.

       Per HSTAR 7223, at 230/084904Z there was a STIS EMC retry.  ROP NS-12
was executed at 230/085621Z to clear the error.

       The STIS MCE-1 reset at 230/134640Z while the high voltage was on and
while outside any SAA interval.  The proposal described in 1.7 may have been
affected.  Per ROP NS-12, the STIS flight software error counter was reset at
230/14432Z.  The MAMA-1 recovery was at 230/1421Z via nominal SMS commanding. 
During the recovery, according to HSTAR 7224, an expected status buffer message
was received but with an unexpected severity level, “informational” versus the
normal “warning”.

3.0 SIGNIFICANT FORTHCOMING EVENTS: 

       Continuation of normal science observations and calibrations.

/DMH