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HUBBLE SPACE TELESCOPE

DAILY REPORT #2681

PERIOD COVERED: 0000Z (UTC) 08/07/00 - 0000Z (UTC) 08/08/00

Daily Status Report as of 221/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

1.1 Completed Four Sets of WF/PC-2 8826 (Cycle 9 Supplemental Darks pt 1)

The WF/PC-2 was used to perform a T dark calibration program that
obtains three dark frames every day in order to provide data for monitoring
and characterizing the evolution of hot pixels. The final iteration of
this proposal was affected by the multiple losses of lock described in 2.1
and HSTAR 7779. ,There were no further reported anomalies.

1.2 Completed STIS/CCD 8439 (Bias Monitor-Part 2 C8)

The Space Telescope Imaging Spectrograph (CCD) was used 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 track the evolution of hot
columns. The proposal completed with no reported problems.

1.3 Completed WF/PC-2 7407 (Continuation of Temporal Monitoring of the
Crab Synchrotron Nebula)

The WF/PC-2 was used to observe the synchrotron nebula surrounding
the Crab pulsar that has been the subject of intensive study for
decades. It is generally accepted that the structure and activity in this
region are due to wave phenomena near the termination shock of the pulsar
wind, observations of which hold unique promise of leading to more complete
models of the pulsar and its magnetosphere. Unfortunately, this promise
has not been fulfilled, largely because of the low spatial resolution and
uneven temporal coverage of existing studies. Recent WF/PC-2 observations
of the Crab synchrotron nebula offer new hope in this quest. These data,
which reach the natural size scale defined by the Larmor radius of
energetic electrons, resolve the majority of the the known features in the
Crab. For the first time it is possible to reliably establish the physical
conditions {e.g., emissivities, equipartition fields, and pressures} of
features associated with the wind and its termination shock. The
observation completed with as planned.

1.4 Completed Two Sets of STIS/CCD 8437 (Dark Monitor-Part 2 C8)

The Space Telescope Imaging Spectrograph (CCD) was used to monitor
the darks. The proposal completed nominally.

1.5 Completed Two Sets of STIS/CCD 8808 (POMS Test Proposal: STIS
Non-Scripted Parallel Proposal Continuation III)

The Space Telescope Imaging Spectrograph (CCD) was used to make
non-scripted, parallel observations as part of a POMS test proposal. The
observations completed with no anomalous activity.

1.6 Completed Two Sets of 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.

1.7 Completed STIS/CCD/MA2 8126 (Observations Of QSO Pairs)

The Space Telescope Imaging Spectrograph (CCD and MA2) was used to
obtain ultraviolet spectra of four QSO pairs with similar common redshift
ranges {z ~ 0.7--1} and projected linear separations gradually increasing
from ~0.5 to sim1 h^-1_100 Mpc. This is being done to: {i} to probe the
extension and structure of gaseous complexes giving rise to the formation
of LyAlpha absorption lines at intermediate redshift {z ~ 0.9}, {ii} to
investigate the transversal proximity effect of the foreground quasar along
the line of sight to the background quasar; and {iii} study the environment
in which QSOs reside and in particular the presence of gas around the
foreground quasar. The observations completed nominally.

1.8 Completed Two Sets of WF/PC-2 8805 (POMS Test Proposal: WFII
Parallel Archive Proposal Continuation)

The WF/PC-2 was used to perform a generic target version of the
WFPC2 Archival Pure Parallel program. The program will be used to take
parallel images of random areas of the sky, following the recommendations
of the Parallels Working. The final iteration of this proposal was
affected by the multiple losses of lock described in 2.1 and HSTAR
7779. Otherwise, the proposal completed with no further reported problems.

1.9 Completed STIS/MA1 8426 (Cycle 8 MAMA Dark Measurements)

The Space Telescope Imaging Spectrograph (MA1) was used to make a
routine Cycle-8 MAMA dark noise calibration measurement. This proposal
will provide the primary means of checking on the health of the MAMA
detectors. This is done through frequent monitoring of the background
count rate. The observations were completed as planned, and no problems
were reported.

1.10 Completed WF/PC-2 8822 (Decontaminations and Associated
Observations Pt. 1/4)

The Wf/PC-2 was used for the monthly decons. Also included are
instrument monitors tied to decons: photometric stability check, focus
monitor, pre- and post-decon internals {bias, intflats, kspots, & darks},
UV throughput check, VISFLAT sweep, and internal UV flat check. There were
no reported problems.

1.11 Completed WF/PC-2 8339 (Light Element Abundance Variations in the
Core of 47 Tucanae)
Abstract

The WF/PC-2 was used to explore the extent of star-to-star light
element variations in the core of the Galactic globular cluster 47
Tucanae. Observations in 47 Tuc have revealed that large star-to-star
differences in sodium, correlated with CN band-strength differences, exist
among its main-sequence turn-off stars, well before any proposed mechanism
for Na production and subsequent mixing could be in operation. The
proposal completed with no reported problems.

1.12 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.

1.13 Completed S/C 5582 (FOC/48 Monthly Activation (Camera Section
Only): Cycle 4)

This proposal was executed as scheduled, and no anomalies were noted.

1.14 Completed WF/PC-2 8593 (Sakurai's Novalike Object: Real-Time
Monitoring of a Stellar Thermal Pulse)

The WF/PC-2 was used to continue a Cycle 7-8 long-term observation
of Sakurai's novalike variable that presents a "once-in-a-lifetime''
opportunity for real-time observations of a star undergoing a final helium
thermal pulse. No anomalous activity was reported.

1.15 Completed FOC/96 7923 (FOC F/96 Turn-on)

The Faint Object Camera (f/96) was used to take an internal flat
and a dark to ensure that the 30-day limit for the FOC is not
exceeded. The observations were executed as scheduled, and no anomalies
were noted.

1.16 Completed WF/PC-2 8609 (Host Galaxy Luminosities of the Most
Luminous QSOs)

The WF/PC-2 was used to determine the factors that decide whether a
galaxy is host to a luminous QSO. Recent evidence indicates that host
galaxy spheroid mass is a key factor: we want to test the relationship
between host galaxy and QSO luminosity at the highest feasible QSO
luminosities by measuring the luminosities and profiles of host galaxies
for QSOs with -25.8 > M_V > -27.6. Current data in this area are
conflicting. The observations completed with no reported anomalies.

1.17 Completed Two Sets of WF/PC-2/STIS/CCD 8196 (High Spatial
Resolution UV/Optical Spectroscopy of H-II Regions in the Magellanic Clouds)

Both the WF/PC-2 and the Space Telescope Imaging Spectrograph (CCD)
were used to make high signal/noise, ultraviolet and optical observations
of the H-II region in the Large Magellanic Cloud known as SMC/N66NW. This
is to make definitive measurements of the abundances of C and N, and to
study the temperature, density, and ionization structures of the
nebulae. A wavelength calibration image was also taken. The observations
were executed as scheduled, and no anomalies were noted.

1.18 Completed 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.

1.19 Completed STIS/CCD/MA1 8219 (A Definitive Census of the
Cataclysmic Variable Population in 47 Tuc)

The Space Telescope Imaging Spectrograph (CCD and MA1) was used to
make deep, far-ultraviolet, time-resolved observations of the cataclysmic
variable population in the globular cluster 47 Tuc (a.k.a., NGC-104). A
wavelength calibration image was also taken. This proposal was affected by
the multiple losses of lock described in 2.1 and HSTAR 7779. Otherwise,
the observations were executed as scheduled, and no further anomalies were
noted.

1.20 Completed WF/PC-2 8544 (POMS Test Proposal: WFII Backup Parallel
Archive Proposal II)

The WF/PC-2 was used to execute a POMS test proposal that was
designed to simulate scientific plans. This proposal was affected by the
multiple losses of lock described in 2.1 and HSTAR 7779. No further
problems were encountered.

2.0 FLIGHT OPERATIONS SUMMARY:

2.1 Guide Star Acquisitions:
Scheduled Acquisitions: 7
Successful: 7
Scheduled Re-acquisitions: 3
Successful: 3

As described in HSTAR 7779, there were multiple losses of lock (at
least eight) after a successful acquisition at 220/224453Z and a successful
re-acquisition at 221/002147Z. Acquiring was re-established by the use of
#44 commands and by real-time maps and fine attitude
determinations. Proposals outlined in 1.1, 1.8, 1.19 and 1.20 were affected.

2.2 FHST Updates:
Scheduled: 14
Successful: 14

2.3 Operations Notes:

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

Per ROP SR-8A, the SSR-1 was configured for autonomous engineering
record at 220/1316Z. Later, the SSR was returned to "normal" operation.

A TTR was generated when no GCMR or UPD capability was available
beginning at 220/1436Z due to an NCC problem.

Another TTR was written for a negative acquisition at 220/1621Z due
to STGT problems. One minute, 8 seconds of recoverable 32k data was lost.

SI C&DH errors were reset at 220/1928Z per ROP NS-5.

Gyro bias calculation in the preview mode was enabled at 220/1702Z.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

Continuation of normal science observations and calibrations.

/CAW