HUBBLE SPACE TELESCOPE

   DAILY REPORT #2851

PERIOD COVERED:  0000Z (UTC) 04/13/01 - 0000Z (UTC) 04/16/01

Daily Status Report as of 106/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 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.

    1.2 Completed Five Sets of WF/PC-2 8699 (The Origin of Short-Period Comets)

        The WF/PC-2 was used to detect and characterize cometary nuclei in 
order to determine the basic physical properties of a large fraction of the 
population of short-period comets.  By acquiring statistically significant 
data, we can study the origin of this family of comets and test the 
hypothesis that they are collisional fragments from the Kuiper Belt 
Objects.  As described in the previous report and in HSTAR 8162, the 
acquisition for the third iteration of this proposal failed, affecting one 
observation.  Then, as described in the previous report and in HSTAR 8163, 
the acquisition for the third iteration of this proposal failed, affecting 
two observations. Otherwise, the observations completed with no further 
reported problems.

    1.3 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.

    1.4 Completed Eight 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.

    1.5 Completed STIS/CCD 8846 (Imaging Flats C9)

        The Space Telescope Imaging Spectrograph (CCD) was used to 
investigate flat-field stability over a monthly period.  The proposal 
completed nominally.

    1.6 Completed STIS/MA2 8863 (NUV-MAMA Cycle 9 Flats)

        The Space Telescope Imaging Spectrograph (MA2) was to be used to 
obtain NUV-MAMA observations of the internal Deuterium lamp to construct an 
NUV flat applicable to all NUV modes.  As described in the previous report 
and in HSTAR 8162, the acquisition this proposal failed, affecting two 
observations.

    1.7 Completed STIS/MA1 8862 (FUV-MAMA Cycle 9 Flats)

        The Space Telescope Imaging Spectrograph (MA1) was to be used to 
obtain FUV-MAMA observations of the internal Krypton lamp to construct an 
FUV flat applicable to all FUV modes.  As described in the previous report 
and in HSTAR 8163, the acquisition for this proposal failed, affecting one 
observation.

    1.8 Completed Six 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.

    1.9 Completed Two Sets of WF/PC-2 8583 (Imaging Snapshots of Asteroids)

        The WF/PC-2 was used to obtain images of the fifty largest main 
belt asteroids that have favorable apparitions during cycle 9.  The images 
will be searched for companion bodies, as well as mineralogical variegation 
on the resolved main bodies.  There were no reported problems.

    1.10 Completed Fourteen 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}.  During the eleventh iteration of this proposal, the re-acquisition 
failure described in 2.1 and HSTAR 8168 occurred, affecting one 
observation.  Otherwise, the observations completed nominally with no other 
reported problems..

    1.11 Completed WF/PC-2 8703 (A Spectacular Post-Starburst Quasar and 
the AGN--Starburst Connection)

        The WF/PC-2 was used to perform broad-band imaging of the 
spectacular post- starburst quasar UN J1025-0040 {V=19, z=0.634}.  The 
optical spectrum is a chimera, dominated in the blue by light from a 
quasar, and dominated in the red by light from a 400-Myr-old starburst with 
a mass possibly as much as 10^11 M_SUN.  The total energy budget of both 
sources appears similar, 10^11.6 L_SUN.  The extended fuzz of the host 
galaxy is asymmetric toward a nearby companion {dominated by an 800-Myr-old 
starburst}, signifiying some kind of interaction.  There were no reported 
problems.

    1.12 Completed Two Sets of WF/PC-2 8677 (Extragalactic Novae: the 
Maximum Magnitude - Rate of Decline Relation in NGC 4472)

        The WF/PC-2 was used to accomplish two goals: {1} to provide the 
first homogeneous observational constraints on theoretical models for novae 
outbursts; and {2} to assess the reliability of novae as standard candles 
by using WFPC2 to collect well sampled light curves for 20-50 novae in the 
supergiant elliptical galaxy NGC 4472, the brightest galaxy within 30 
Mpc.  Both the length of the observing window and the temporal sampling of 
the observations are specifically designed to ensure that the novae peak 
magnitudes and decline rates are measured accurately.  These data will be 
used to construct the first `Maximum Magnitude versus Rate of Decline' 
{MMRD} relation for a galaxy beyond the Local Group.  This relation is not 
only a potentially powerful standard candle, but its shape and dispersion 
are directly linked to physical parameters which govern the physics of 
novae outbursts such as the white dwarf mass, temperature and mass 
accretion rate.  The proposal completed with no reported problems.

    1.13 Completed WF/PC-2 8655 (Geometric Distances of Globular Clusters 
{GO part})

        The WF/PC-2 was used to establish a globular-cluster distance scale 
of unprecedented accuracy and reliability, with far- reaching impact on the 
distance and time scales of cosmology.  Our method is to compare internal 
dispersions of proper motion with ground-based determinations of the 
dispersion of radial velocities.  The prospect is a geometrically based 
distance scale with an accuracy of better than 2 ability to make such 
measurements, and we are progressing with the conversion of them to a 
distance for the cluster.  The observations completed with no reported 
problems.

    1.14 Completed 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.

    1.15 Completed STIS/CCD 8603 (Secular Changes In The Temperatures And 
Radii Of Extreme Helium Stars)

        The Space Telescope Imaging Spectrograph (CCD) was used to make 
observations of 15 extreme helium stars (EHEs_ which, together with IUE 
data, will give a 20-year baseline of ultraviolet spectrophotometry.  EHEs 
are luminous stellar remnants evolving rapidly to become white 
dwarfs.  They represent an important stage in the evolution of at least 
some low-mass stars, and are closely related to the R Coronae Borealis 
variables.  Models do not agree about their origin, nor about what fraction 
of normal stars pass through this phase, in which the stars have been 
completely stripped of their outer layers.  The models do predict that EHEs 
are contracting and provide rate predictions and evolutionary 
lifetimes.  The observations completed with no reported problems.

    1.16 Completed FGS/1 8774 (Calibrating the Mass-Luminosity Relation at 
the End of the Main Sequence)

        The Fine Guidance Sensor #1 was used to calibrate the 
mass-luminosity relation {MLR} for stars less massive than 0.2 Msun, with 
special emphasis on objects near the stellar/brown dwarf border.  Our goals 
are to determine Mv values to 0.10 magnitude, masses to 5%, and more than 
double the number of objects with masses determined to be less than 0.20 
Msun.  The proposal completed with no reported problems.

    1.17 Completed Seven 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.

    1.18 Completed STIS/CCD/MA1/MA2 8877 (Simultaneous HST and Chandra 
Observations of the X-Ray/UV absorbers in Seyfert 1 Galaxies)

        The Space Telescope Imaging Spectrograph (CCD, MA1 and MA2) was 
used to make UV and X-ray observations of intrinsic absorption that reveal 
that outflowing photoionized gas with a substantial covering factor is a 
major nuclear component in at least 50% of Seyfert 1 galaxies.  X-ray 
observations suggest multiple zones with highly variable ionization states 
and column densities. UV observations reveal multiple kinematic components, 
with column densities that vary in time.  This variability indicates that 
simultaneous UV and X-ray observations at high spectral resolution are the 
only way to decipher the complex kinematic and ionization structure and the 
true connection between UV and X-ray absorbers, and hence form an accurate 
picture of the environs of the inner nucleus.  The observations completed 
with no reported problems.

    1.19 Completed STIS/CCD/MA1 8473 (Key Project: The Nuclear Region Of 
NGC 4151 Observations)

        The Space Telescope Imaging Spectrograph (CCD and MA1) was used to 
observe the Seyfert 1 galaxy NGC 4151.  This galaxy will be studied in 
several ways. 1} low-resolution spectra over the entire UV and visible 
range will be obtained through a slit at several different orientations to 
model the physical conditions in the emission-line regions; 2} slitless and 
long-slit spectra of strong emission lines at moderate resolution and 
narrow-band WFPC2 images will be used to map the dynamics of the regions; 
3} echelle spectra over the entire UV bandpass will be used to study the 
intrinsic absorption in the nucleus; and 4} parallel imaging will be 
performed of the outer galaxy and other galaxies or QSOs.  There were no 
reported problems.

    1.20 Completed Two Sets of STIS/CCD/MA1 8662 (A Snapshot Survey of the 
Hot Interstellar Medium)

        The Space Telescope Imaging Spectrograph (CCD And MA1) was used to 
obtain snapshot STIS echelle observations of key tracers of hot 
interstellar gas {C IV, N IV, and Si IV} for selected FUSE Team O VI survey 
targets with known UV fluxes.  By taking advantage of the snapshot 
observing mode we will efficiently obtain a large number of spectra 
suitable for the study of the highly ionized hot component of the 
interstellar medium {ISM}.  Our goals are to explore the physical 
conditions in and distribution of such gas, as well as to explore the 
nature of the interfaces between the hot ISM and the other interstellar gas 
phases.  The observations completed with no reported problems.

    1.21 Completed Two Sets of STIS/CCD 8776 (Absolute Proper Motions of 
Nearby Dwarf Spheroidal Galaxies)

        The Space Telescope Imaging Spectrograph (CCD) was used to measure 
precise absolute proper motions for four dwarf spheroidal satellites of the 
Milky Way using spectroscopically-confirmed background QSOs to define a 
zero- velocity reference frame.  No anomalous activity was reported.

    1.22 Completed STIS/CCD 8687 (Elliptical Galaxies With Nuclear Disks of 
Stars: Black Hole Search and Stellar Populations)

        The Space telescope Imaging Spectrograph (CCD) was used to observe 
galaxies NGC 3706 {E3} and NGC 4486A {E2} to search for supermassive black 
holes {BHs}.  NGC 3706 contains a bright, edge-on nuclear disk of 
stars.  Therefore we can measure the BH mass mbh as easily as in a galaxy 
with a gas disk but without uncertainty about whether the motions are 
affected by non-gravitational forces.  NGC 4486A, like NGC 4486B, is a 
dwarf elliptical companion of NGC 4486 {M s87} with signs of an unusually 
massive BH.  The observations completed and no anomalous activity occurred.

    1.23 Completed Two Sets of WF/PC-2/STIS/CCD/MA2 8568 (A Seminal 
Spectroscopic and Imagery Investigation of the Brightest Wolf-Rayet Shell 
Nebula: NGC 6888)

        The WF/PC-2 (for imagery) and the Space Telescope Imaging 
Spectrograph (CCD for UV-optical-NIR spectroscopy of several regions in the 
brightest Wolf-Rayet Shell) were used to observe Nebula {WRSN}, NGC 
6888.  The physical conditions in the wind-driven and/or stellar ejected 
plasma {temperature, density, ionization, and composition} of WRSN, which 
are dominated by strong stellar winds from hot massive stars in an advanced 
state of evolution, often involve emission from both shock-ionized and 
photoionized gas in close proximity.  These new observations will comprise 
the first combined spectroscopy and imagery of a WRSN at a resolution 
sufficient to separate and individually analyze these two emission 
regions.  The proposal completed nominally with no reported problems.

    1.24 Completed STIS/CCD 8845 (Spectroscopic Flats C9)

        The Space Telescope Imaging Spectrograph (CCD) was used to obtain 
CCD flats in the spectroscopic mode.  The observations completed with no 
reported problems.

    1.25 Completed WF/PC-2 8698 (Identification of the Galaxy's Missing Mass)

        The WF/PC-2 was used to observe the nature of dark matter that is 
one of the key astrophysical questions of the day.  The existence of dark 
matter and its dynamical dominance in the outer parts of our Galaxy and 
spiral galaxies with flat rotation curves is well established.  The MACHO 
project has identified ~half of the Milky Way's dark matter with stellar 
objects of ~0.5 M_sun, probably white dwarfs.  But the location of the 
microlensing in the halo is disputed.  Several have detected two candidate 
halo white dwarfs of L/L_sun ~ 10^-5 in the Hubble Deep Field with 25 +/- 5 
mas/year proper motions.  The observations completed with no reported problems.

    1.26 Completed WF/PC-2 8780 (Secular Changes in the Jet of M87)

        The WF/PC-2 was used to continue the ongoing investigation of the 
M87 jet that had previously used the FOC.  The investigators will compare 
FOC and WFPC2 images to track secular changes and motions in the jet and 
nucleus.  During this proposal, the re-acquisition failure described in 2.1 
and HSTAR 8168 occurred, affecting five observations.  Otherwise, the 
observations completed nominally.

    1.27 Completed WF/PC-2 8173 (Alignment and Evolution of Redshift One 
Radio Galaxies)

        The WF/PC-2 was used to observe galaxies associated with powerful 
distant radio sources which are the most massive ellipticals known at early 
cosmic epochs, and are also uniquely important for understanding the 
physics of AGN and the interactions between the radio source and its 
environment.  The observations completed with no reported problems.

    1.28 Completed STIS/CCD 8667 (Nuclear Stellar Disks in Early Galaxies: 
Black Hole Masses and Disk/Bar/Bulge Evolution)

        The Space Telescope Imaging Spectrograph (CCD) was used to image of 
an additional four E/SO galaxies to: {1} test whether the unusual 
M_bh/M_bulge ratio is typical of these nuclear disk galaxies and {2} search 
for additional ring/bar structures will help determine the source of the 
accreted material and the time sequence of the disk/bar/bulge/Black Hole 
fueling connection.  The observations completed with no reported anomalies.

2.0 FLIGHT OPERATIONS SUMMARY:

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

  Scheduled Re-acquisitions: 27
Successful: 26

        Per HSTAR 8168, the re-acquisition at 105/095204Z failed when the 
scan step limit was exceeded on FGS-2.  The proposals detailed in 1.10 and 
1.26 were affected.

    2.2 FHST Updates:
Scheduled: 48
Successful: 48

    2.3 Operations Notes:

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

        The SSR pointer was set at 104/1212Z as directed by ROP SR-3.

        There was a STIS EMC re-try at 104/192530Z.  The STIS flight 
software error counter was cleared at 104/2024Z per ROP NS-12.

        A TTR was written for a required re-transmit at 106/081845Z during 
a command load uplink.

        The CCS engineering status buffer limits were adjusted at 
106/0826Z, using ROP DF-18A.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW