HUBBLE SPACE TELESCOPE

   DAILY REPORT #2919

PERIOD COVERED:  0000Z (UTC) 07/20/01 - 0000Z (UTC) 07/23/01

Daily Status Report as of 204/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Twenty-eight Sets of STIS/CCD 9248 (Probing the Large 
Scale Structure: Cosmic Shear Observations)

        The Space Telescope Imaging Spectrograph (CCD) was used to measure 
the distortion of light bundles from distant galaxies that probe the 
statistical properties of the intervening inhomogeneous {dark} matter 
distribution.  Its tidal gravitational field distorts the observable image 
shapes thereby causing a coherent ellipticity pattern {Cosmic Shear}.  As 
documented in 2.1 and HSTAR 8278, the acquisition for the twenty-second 
iteration of this proposal defaulted to fine lock backup on one FGS only, 
possibly affecting one observation.  Otherwise, the observations completed 
nominally.

    1.2 Completed Six 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.

    1.3 Completed Eight 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.

    1.4 Completed Five Sets of WF/PC-2/STIS/CCD 8559 (The Role of Dark 
Matter in Cluster Formation and Galaxy Evolution)

        The WF/PC-2 and the Space Telescope Imaging Spectrograph (CCD) were 
used to observe the outer regions of massive clusters that represent 
transitional areas of great cosmological importance where field galaxies 
encounter the steep potential wells of dark matter and baryonic hot 
gas.  Little is known about either the dark matter profile at large radii 
or the morphological properties of infalling galaxies at those redshifts 
where strong evolution is observed in the cluster cores.  The proposal 
completed normally, with no reported problems.

    1.5 Completed Nineteen Sets of WF/PC-2 9252 (Cycle 10 Clocks On Check)

        The WF/PC-2 was used to perform closure calibration for clocks 'on' 
mode, which obtains dark frames in order to provide data to create a clocks 
'on' super dark calibration reference file, to monitor and characterize the 
evolution of hot pixels, and to obtain standard star observations for 
photometric calibration.  The proposal completed with no reported anomalous 
activity.

    1.6 Completed Three Sets of STIS/CCD 8865 (Bias Monitor-Part 2)

        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 anomalous activity.

    1.7 Completed Five Sets of WF/PC-2 9160 (Disks and Envelopes of Nearby 
Nebulous Young Stellar Objects: A Snapshot Survey)

        The WF/PC-2 was used to perform a snapshot survey of nearby 
nebulous young stellar objects to study the detailed morphology of the 
their disks and envelopes and probe the effect of inclination on the 
infrared spectral energy distribution of disk/envelope systems.  As 
documented in 2.1 and HSTAR 8278, the acquisition for the twenty-second 
iteration of this proposal defaulted to fine lock backup on one FGS only, 
possibly affecting two observations.  Otherwise, the observations completed 
nominally.

    1.8 Completed WF/PC-2 9255 (Cycle 10 WF/PC-2 Astrometric Effects of CTE)

        The WF/PC-2 was used to quantify the astrometric effects of CTE by 
measuring: {1} the relative separation of a bright source vs. a faint 
target at different positions on the PC1 CCD and {2} the relative motion of 
a source on the CCD compared to very precise slews performed with the 
FGSs.  These tests will be conducted for point and extended targets at 
several different intensity levels.  No problems were encountered.

    1.9 Completed WF/PC-2 8585 (Cosmological Parameters from Type Ia 
Supernovae at High Redshift)

        The WF/PC-2 was used to measure the cosmological parameters, Omega, 
Lambda, and thus the curvature, Omega_k, using Type Ia supernovae {SNe Ia} 
as calibrated standard candles.  There were no reported problems.

    1.10 Completed WF/PC-2 8581 (A Search For Low-Mass Companions To 
Ultracool Dwarfs)

        The WF/PC-2 was used to search for very low-mass {VLM} companions 
to a complete sample of 120 late-M and L dwarfs, drawn mainly from the 
2MASS and SDSS surveys.  The primary goal is to determine the multiplicity 
of M < 0.1 M_odot dwarfs.  In particular, we aim to identify binary systems 
suitable for long-term astrometric monitoring and mass measurement, and 
systems with cool, sub-1000K companions.  The proposal completed with no 
reported problems.

    1.11 Completed Three Sets of FGS/1 9097 (The Mass-Luminosity 
Relationship for High Mass Stars: Resolving the `Mass Discrepancy' with HST)

        Fine Guidance Sensor #1 was used to investigate the mass-luminosity 
relation for very low mass stars.  This relationship is well determined for 
intermediate-mass stars.  The observations completed with no reported problems.

    1.12 Completed Ten 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.

    1.13 Completed Two Sets of STIS/CCD 9121 (Evolution of the Host 
Galaxies in Low- Power AGN)

        The Space Telescope Imaging Spectrograph (CCD) was used to study 
the evolution of low-power AGN host galaxies to z~1.3, allowing the direct 
study of how the formation and life cycles of radio-loud AGN depend on 
intrinsic power.  There were no reported problems.

    1.14 Completed WF/PC-2 9158 (Observatory Focus Monitor)

        The WF/PC-2 was used to check the observatory focus since it is 
known that the HST focus drifts slowly and shows evidence of undergoing 
slips of a few microns at random times.  The rate of the WF/PC-2 monitoring 
program is insufficient to track and/or understand OTA behavior in order to 
request timely and appropriate Secondary Mirror corrections.  This 13-orbit 
program obtains a large amount of high signal-to-noise focus data, 
sometimes in two science instruments at once, and will be sufficient to 
more accurately define the HST focus.  The utility of STIS image phase 
retrieval will be thoroughly tested with OII and OIII images acquired in 
parallel with WFPC2 images.  The proposal completed without incident.

    1.15 Completed Two Sets of STIS/CCD 9063 (Optical Counterparts of 
Isolated Neutron Stars)

        The Space Telescope Imaging Spectrograph (CCD) was used to test the 
understanding of both quantum chromodynamics {QCD} and quantum 
electrodynamics {QED}.  Specifically, the measurement of radii of neutron 
stars can test QCD at high density.  This is being realized through 
intensive X-ray observations of bright nearby neutron stars.  However, the 
natures of these important sources are not clear and to this end a simple 
proper motion program is proposed as a means to obtain their ages and 
potential association with star-forming regions.  One of the sources is RX 
J0720.4-3125 which has been argued to be an old magnetar --- a highly 
magnetized neutron star --- and thanks to its high count rate is already a 
choice object for X-ray missions.  Magnetars, with their extreme magnetic 
field strengths, are excellent laboratories for testing out some 
expectation of QED.  There were no reported problems.

    1.16 Completed WF/PC-2 9133 (Imaging of Gravitational Lenses)

        The WF/PC-2 was used to observe gravitational lenses that offer 
unique opportunities to study cosmology, galactic structure, galaxy 
evolution, quasar hosts and extinction.  They are also the only sample of 
galaxies selected on the basis of their mass rather than their luminosity 
or surface brightness.  While gravitational lenses can be discovered with 
ground-based optical and radio observatories, converting them from 
curiosities into scientific tools requires HST.  There were no reported 
anomalies.

    1.17 Completed FGS/1 9168 (The Distances to AM CVn Stars)

        Fine Guidance Sensor (FGS) #1 was used to determine the parallaxes 
and proper motions of the five brightest of the seven known AM CVn systems 
using the HST FGSs.  AM CVn systems are binaries where mass is transferred 
from a completely hydrogen-deficient, degenerate mass donor to a white 
dwarf primary through a helium accretion disk.  A better understanding of 
these systems is crucial for a number of reasons: (1) to study the late 
stages of binary evolution, (2) to study the effect of chemical composition 
on the physics of accretion discs, (3) to estimate their contribution to 
the Supernovae Ia rate, and (4) to estimate their contribution to the 
gravitational radiation background.  All observations completed with no 
reported problems.

    1.18 Completed WF/PC-2 9124 (Mid-UV SNAPSHOT Survey of Nearby 
Irregulars: Galaxy Structure and Evolution Benchmark)

        The WF/PC-2 was used to investigate the relation between star 
formation and the global physical characteristics of galaxies to interpret 
the morphologies of distant galaxies in terms of their evolutionary 
status.  Distant galaxies are primarily observed in their rest frame 
mid-ultraviolet.  They resemble nearby late-type galaxies, but are they 
really physically similar classes of objects?  It is proposed to address 
this question through a SNAPSHOT survey in the 2 mid-UV filter F300W of 98 
nearby late-type, irregular and peculiar galaxies.  No problems were reported.

    1.19 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.

    1.20 Completed WF/PC-2 8632 (A UV Atlas of Nearby Galaxies)

        The WF/PC-2 was used to perform a snapshot survey of local galaxies 
at UV wavelengths with the F300W filter.  The aim of the project is to 
build a reference UV Atlas of normal galaxies, whose optical images are 
well known, with the highest possible degree of information, covering all 
the morphological types and luminosity classes.  The proposal completed 
normally.

    1.21 Completed Three Sets of WF/PC-2 8820 (Wavelength Stability of 
Narrow Band and Linear Ramp Filters)

        The WF/PC-2 was used to verify the mapping of wavelength as a 
function of CCD position on linear ramp filters and to check for changes in 
central wavelengths of the narrow band filters.  The proposal completed 
nominally.

    1.22 Completed WF/PC-2 8719 (A Continuation Of A Snapshot Survey Of X- 
Ray Selected Central Cluster Galaxies)

        The WF/PC-2 was used to perform snapshot images of a representative 
subset of the central cluster galaxies from an X-ray selected cluster 
sample that would provide important constraints on the formation and 
evolution of dust in cluster cores that cannot be obtained from 
ground-based observations.  The observations completed as planned.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 22
Successful: 22

        As detailed in HSTAR 8278, the acquisition at 203/022940Z defaulted 
to fine lock backup on FGS-2 only when the scan step limit was exceeded on 
FGS-1.  The proposals described 1.1 and 1.7 may have been affected.
  Scheduled Re-acquisitions: 17
Successful: 17

    2.2 FHST Updates:
Scheduled: 50
Successful: 50

    2.3 Operations Notes:

        Real-time operations returned to the Science Institute at 201/1150Z.

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

        A TTR was written for a required re-transmit at 203/0320Z during an 
NSSC-1 uplink.  The SI C&DH was reset at 203/0322Z per ROP NS-5.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW