HUBBLE SPACE TELESCOPE

   DAILY REPORT #2818

PERIOD COVERED:  0000Z (UTC) 02/27/01 - 0000Z (UTC) 02/28/01

Daily Status Report as of 059/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Three Sets of WF/PC-2 8827 (Cycle 9 Supplemental Darks pt2/3)

        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 nominally.

    1.2 Completed Two Sets of STIS/CCD 8837 (CCD Dark Monitor-Part 1)

        The Space Telescope Imaging Spectrograph (CCD) was used to monitor 
the darks.  The proposal completed with no reported problems.

    1.3 Completed WF/PC-2/STIS/CCD 8690 (The Central Region of NGC4696: 
Manifestation of the Physics of Mergers?)

        The WF/PC-2 and the Space Telescope Imaging Spectrograph (CCD) were 
used to observe massive, dominant ellipticals with attendant emission-line 
gas, dust and hot, heavy X--ray emitting coronae which lie at the very 
centers of galaxy clusters.  The physics of these complex, high pressure 
regions remains controversial:  Are cooling flows responsible?  Do mergers 
dominate, with massive accretion events triggering an array of 
phenomena?  Is the AGN crucial?  A major impetus to understanding the 
physics of these regions will come with Chandra.  NGC4696 in the Centaurus 
galaxy cluster is archetypal.  WFPC2 images have shown a dramatic 
bifurcation between gas and dust. T he nucleus itself is seen to be a 
compact triple, with two blue components straddling a third red one.  We 
propose to obtain STIS long- slit spectra along a line-emission filament 
and along a dust filament.  The proposal completed with no reported problems.

    1.4 Completed STIS/CCD/MA2 8673 (The Properties of Ly-Alpha Absorbers 
at Redshifts Between 0.9HST)

        The Space Telescope Imaging Spectrograph (CCD and MA2) was used 
obtain new Echelle resolution spectra of three bright quasars which, when 
combined with archived and scheduled observations, will be used to 
characterize the properties of Ly-Alpha absorbers in the redshift range 
0.9<z<1.6.  There were no reported problems.

    1.5 Completed Three 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 Group.  The proposal completed with no reported 
problems.

    1.6 Completed Four Sets of WF/PC-2 8816 (Cycle 9 UV Earthflats)

        The WF/PC-2 was used to obtain sequences of Earth streak flats to 
improve the quality of pipeline flat fields for the WFPC2 UV filter set and 
in order to monitor flat field stability.  There were no reported problems.

    1.7 Completed Two Sets of WF/PC-2 8811 (Cycle 9 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.

    1.8 Completed STIS/CCD 8624 (Imaging and Spectroscopy of Dusty 
Circumstellar Disks)

        The Space Telescope Imaging Spectrograph (CCD) was used to further 
understanding of the properties and evolution of dusty disks in the 
circumstellar environments of young stars which is a key element in 
furthering our concepts of the formation mechanisms of extra-solar 
planetary systems.  The proposal completed with no reported problems.

    1.9 Completed Eight Sets of STIS/CCD 8562 (Probing the Large Scale 
Structure: Cosmic Shear Observations)

        The Space Telescope Imaging Spectrograph (CCD) was used to probe 
the distortion of light bundles from distant galaxies, looking at the 
statistical properties of the intervening inhomogeneous {dark} matter 
distribution.  The proposal completed nominally.

    1.10 Completed WF/PC-2 8604 (Stellar Populations Across the Small 
Magellanic Cloud (SMC) : History and Structure)

        The WF/PC-2 was used to investigate the structure and evolutionary 
history of the SMC by obtaining a series of 50 three-color snapshots of 
selected SMC regions.  With this polling of SMC field star properties, we 
will produce color-magnitude diagrams in the U, V and I bands which will 
reach V~23.5 in regions too crowded to be observed accurately from the 
ground.  The observations completed nominally.

    1.11 Completed WF/PC-2 8720 (Masses and Multiplicity of Nearby Free- 
floating Methane and L Dwarfs)

        The WF/PC-2 was used to observe 50 very-low-mass objects in the 
solar neighborhood with spectral types of L0 and later {including several 
dwarfs with Methane absorption bands in their atmospheres}.  These objects 
will be observed in two filter bands with the aim to identify close 
companions, measure their colors, and to obtain first epoch data of the 
newly discovered binaries.  The observations completed nominally.

    1.12 Completed STIS/CCD 8838 (Bias Monitor - Part 1)

        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 nominally.

    1.13 Completed WF/PC-2 8598 (Snapshot Survey of Extended OIIl Lambda 
5007Angstrom Emission in Seyfert Galaxies)

        The WF/PC-2 was used for a snapshot survey of narrow band OIII 
Lambda 5007Angstrom images for a well defined sample of 88 Seyfert galaxies 
{29 Seyfert 1s and 59 Seyfert 2s}, 18 of which already have data in the 
archive, selected from a mostly isotropic property, the 60Mum flux.  These 
data will be used: 1} to determine the origin of the misalignment between 
the accretion disk axis and the host galaxy plane axis, which can be due to 
mergers with other galaxies, or by the self induced radiation warping; 2} 
to compare the size and shape of the Narrow Line Regions (NLR) of Seyfert 
1s and Seyfert 2s, and to study the frequency of conically shaped NLR in 
Seyfert galaxies, which are usually unresolved from ground-based 
observations; and 3} estimate the importance of shocks to the ionization of 
the NLR.  The observations completed with no reported problems.

    1.14 Completed Two Sets of WF/PC-2 8705 (External Shear in the 
Time-Delay Lens RX J0911+05)

        The WF/PC-2 was used to map the mass distribution in the vicinity 
of the multiple QSO system RX J0911+05 using weak gravitational 
lensing.  This object has emerged as one of the most promising candidates 
for a cosmological determination of the Hubble constant using time delay 
measurements.  There is evidence that a high-redshift cluster of galaxies 
acts as the source of a very large external shear, affecting the lens 
potential.  Deep WFPC2 images will allow direct measurement of this shear 
from the distortions of faint background galaxies.  The proposal completed 
with no reported problems.

    1.15 Completed STIS/CCD/MA2 8652 (Evolution of the Extinction Curve)

        The Space Telescope Imaging Spectrograph (CCD and MA2) was used to 
examine the extinction curve that has been determined precisely in only a 
few galaxies: the Milky Way {MW}, the Large and Small Magellanic clouds 
{LMC and SMC}.  It has also been determined towards several starburst 
galaxies, but its significance then depends on the precise star-gas-dust 
geometry.  There is no general agreement on a model to explain its 
characteristics; laboratory experiments fail to reproduce the famous 
2175Angstrom feature under the conditions of the popular silicate-graphite 
model.  The MW, LMC and SMC extinction curves are generally used to bracket 
extinction curves in other galaxies.  Extinction by dust influences the 
determination of the Hubble constant from cepheids, of Omega_mathrm M and 
Lambda using Type Ia Supernovae or gravitational lenses, of the 
cosmological density of gas and star formation history and the origin the 
Cosmic Infrared Background.  The proposal completed with no reported problems.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions:  7
Successful:  7

  Scheduled Re-acquisitions:  8
Successful:  8

    2.2 FHST Updates:
Scheduled: 13
Successful: 13

    2.3 Operations Notes:

        Operations personnel supported GSFC Internal Simulation #5 (EVA-4) 
yesterday from 8:00 a.m. until approximately 7:30 p.m.

        The SSR EDAC error counter was cleared twice per ROP SR-1A.

        A TTR was written for a required re-transmit at 058/115938Z during 
a NSSC-1 load uplink.

        An SI C&DH error was reset at 058/1203Z, using ROP NS-5.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW