Hubble Space Telescope Daily Report #2940 – 21 Aug 2001

HUBBLE SPACE TELESCOPE

DAILY REPORT #2940

PERIOD COVERED: 0000Z (UTC) 08/20/01 – 0000Z (UTC) 08/21/01

Daily Status Report as of 233/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

1.1 Completed Two Sets of STIS/CCD 8864 (CCD Dark Monitor-Part 2)

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

1.2 Completed Five Sets of WF/PC-2 8935 (Cycle 10 Standard Darks)

The WF/PC-2 was used to obtain 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. Over an extended
period these data will also provide a monitor of radiation damage to the
CCDs. The proposal completed with no reported problems.

1.3 Completed STIS/CCD 9128 (A Snapshot Survey of Absorption Lines from
High Velocity Clouds in the Milky Way)

The Space Telescope Imaging Spectrograph (CCD) was used to search
for Mg II and Mg I absorption from Galactic High Velocity Clouds {HVCs}
along the sightlines of 51 of the brightest QSOs, BL Lacs and Seyfert 2
galaxies in the sky. The observations completed with no rpeorted problems.

1.4 Completed STIS/CCD 8865 (Bias Monitor-Part 2)

The Space Telescope Imaging Spectrograph (CCD) was used to monitor
the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1, and 1×1 at
gain = 4, to build up high-S/N superbiases and track the evolution of hot
columns. The proposal completed with no anomalous activity.

1.5 Completed STIS/CCD/MA1 8306 (Lyman Alpha Clouds toward PKS1302-102)

The Space Telescope Imaging Spectrograph (CCD and MA1) was used to
conduct high spectral resolution observations of the low-redshift quasar
PKS1302-102, whose line of sight comprises ~20 Lyman Alpha absorbers with
HI column densities in excess of 10^14 cm^- 2. The observations completed
nominally.

1.6 Completed Two Sets of WF/PC-2 9244 (POMS Test Proposal: WFII
Parallel Archive Proposal Continuation)

The WF/PC-2 was used to perform a generic target version of the
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 Group. The observations completed with no anomalous
activity.

1.7 Completed Two Sets of WF/PC-2 8828 (Cycle 9 Supplemental Darks pt3/3)

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 proposal completed with no reported problems.

1.8 Completed WF/PC-2 8939 (Cycle 10 Internal Monitor)

The WF/PC-2 was used to calibrate the internal monitor, to be run
weekly to monitor the health of the cameras. No problems were encountered.

1.9 Completed WF/PC-2 9043 (Cepheid Distances to Early-type Galaxies)

The WF/PC-2 was used to continue observations in the HST Key
Project on the Extragalactic Distance Scale and the HST project on the
“Calibration of Nearby Type Ia Supernovae” that have greatly improved our
knowledge of the Hubble Constant by providing a solid zero point for the
Tully- Fisher {TF} relation and Type Ia Supernovae {SNIa}. However, severe
inconsistencies remain for distance estimators to early-type galaxies such
as surface brightness fluctuations {SBF}, the planetary nebula luminosity
function {PNLF}, the fundamental plane {FP}, and the globular cluster
luminosity function {GCLF}. As a result, the distance to the Virgo cluster
core remains uncertain by as much as 20 determination is directly affected
by a lingering 0.1 mag {5 uncertainty in the photometric calibration of the
WFPC2. Resolving these issues is essential not only to firm up the
extragalactic distance scale, but also to understand the mass and velocity
structure of the local universe. SBF in particular is emerging as the
method of choice for mapping local velocity fields to 10, 000 kms because
it offers an order of magnitude less Malmquist bias than TF, and SNIa are
too rare to study large scale flows effectively. This project will tighten
the photometric calibration of the WFPC2, and provide a solid Cepheid
calibration for SBF and PNLF. The observations completed nominally.

1.10 Completed STIS/CCD 8841 (Hot Pixel Annealing C9)

The Space Telescope Imaging Spectrograph (CCD) was used to improve
the effectiveness of the CCD hot pixel annealing process. This is assessed
by measuring the dark current behavior before and after annealing and by
searching for any window contamination effects. In addition CTE
performance is examined by looking for traps in a low signal level
flat. The observations completed with no reported problems.

1.11 Completed Two Sets of WF/PC-2 8867 (Gamma-Ray Bursts: Discovering
The Progenitors And Understanding The Explosion – Visits A0-R0)

The WF/PC-2 was used to observe a gamma-ray burster,
GRB000131. Gamma-ray burst astronomy, one of the most active and exciting
frontiers in astrophysics, is now entering a critical stage — with
dramatic leaps in understanding of these events, as well as new
discoveries. Improvements in triggering and positioning accuracy provided
by the SAX and HETE-2 gamma-ray satellites will allow entirely new classes
of events to be studied. Given the recent progress in this field, the
proposers are now in a position to design precision, broadband measurements
that can provide quantitative information on the as-yet unknown energy
sources, the explosion geometry, and the surrounding medium. In
particular, the growing evidence of an intimate connection between SNe and
GRBs can be definitively tested. The proposal completed with no reported
problems.

1.12 Completed WF/PC-2 9135 (A New High-Z Galaxy Cluster with
Extraordinary Lensed Arcs From Multiple Sources)

The WF/PC-2 was used to observe strong lensing by a relatively high
redshift {z~0.7} cluster in the Red-Sequence Cluster. This lens system has
more bright arcs, with better cluster azimuthal coverage than examples of
lower z lenses previously imaged. At least 4 separate arcs are detected in
our initial survey data, at 3-4 different cluster-centric radii and hence
likely corresponding to at least 3 different background sources at 3
different redshifts. Moreover, these arcs are relatively bright and hence
redshifts should be readily obtainable using 8m class telescopes. All
observations completed normally.

1.13 Completed FGS/1 9169 (An Interferometric Harvest of Double
Degenerates)

Fine Guidance Sensor #1R was used to observe the white dwarf mass
and age distributions that hold clues to the star formation history of our
Galaxy and the age of the disk. No problems were reported.

1.14 Completed WF/PC-2 9042 (An Archive To Detect The Progenitors Of
Massive, Core-Collapse Supernovae)

The WF/PC-s was used to search for supernovae which have massive
star progenitors. The already extensive HST archive and high-resolution
ground-based images of galaxies within ~20 Mpc enables us to resolve and
quantify their individual bright stellar content. As massive, evolved
stars are the most luminous single objects in a galaxy, the progenitors of
core-collapse supernovae should be directly detectable on pre-explosion
images. One Type II progenitor has been observed this year, and the
investigators have proposed a short, companion WFPC2 proposal to confirm
this candidate and identify a second. The observations completed nominally.

2.0 FLIGHT OPERATIONS SUMMARY:

2.1 Guide Star Acquisitions:

Scheduled Acquisitions: 9

Successful: 9

Scheduled Re-acquisitions: 5

Successful: 5

2.2 FHST Updates:

Scheduled: 22

Successful: 22

2.3 Operations Notes:

A meeting concerning the recent motor current jump to 196.0 mAmps
for gyro #3 was held yesterday. In the short term, the CCS ground
operational limits have been adjusted to 200 mAmps in order to catch
another jump. Flight software limits for motor current, now set at 300
mAmps for 90 seconds, are acceptable. PCS SEs have issued an operations
request to power on gyro #1 should a zero-gyro sunpoint (ZGSP) entry
occur. Approved SAC loads have been prepared for a 1, 4, 2, 6 (with 6 in
shadow mode) gyro configuration. PCS SEs is researching archived data to
compare this and other motor current jumps (which were probable step
functions) with the gyro #5 failure (which was a jump with an
overshoot). Other analysis is ongoing.

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

The ephemeris load was uplinked at 233/0056Z as directed by ROP DF-7A.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

Flight software 2.0B RAM installation, 2.0B EEPROM, 2.0C RAM
installation and 2.0C EEPROM installations are scheduled incrementally for
later today and for the following two days. Should further problems arise
with gyro #3, these installations would be postponed.

Continuation of normal science observations and calibrations.