HUBBLE SPACE TELESCOPE

   DAILY REPORT #2837

PERIOD COVERED:  0000Z (UTC) 03/26/01 - 0000Z (UTC) 03/27/01

Daily Status Report as of 086/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Two 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 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 Four Sets of 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.

    1.4 Completed 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.

    1.5 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.

    1.6 Completed Four 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.

    1.7 Completed STIS/CCD/MA1/MA2 8635 (A Test Of Pulsation And Diffusion 
Theory For Subluminous B Stars)

        The Space telescope Imaging Spectrograph (CCD, MA1 and MA2) was 
used to confirm the recent discovery of radial and nonradial mode 
pulsations in nearly 20 sdB stars that makes it possible to use 
asteroseismology to probe the internal structure of these stars and discern 
their evolutionary status. This is needed for reasons as diverse as 
understanding the late stages of stellar evolution and the calibration of 
the observed ultraviolet upturn in giant elliptical galaxies as an age 
indicator.  The observations completed with no anomalous activity.

    1.8 Completed Three Sets of STIS/MA1/MA2 8843 (Cycle 9 MAMA Dark 
Measurements)

        The Space Telescope Imaging Spectrograph (MA1 and MA2) was used to 
perform the routine monitoring of the MAMA detector dark noise.  The 
proposal completed nominally.

    1.9 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 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 
observations completed as planned.

    1.10 Completed STIS/CCD 8572 (Identifying Normal Galaxies at 1.3 < z < 2.5)

        The Space Telescope Imaging Spectrograph (CCD) was used to perform 
studies of faint, distant galaxies.  It is now possible to observe hundreds 
of galaxies out to z=1 and in the range 3 < z < 4.5, yet the redshift range 
1 < z <3 remains largely unexplored.  No problems were noted.

    1.11 Completed STIS/CCD 8236 (Black Holes and Gas Disks in a Complete 
Sample of Radio-Loud Ellipticals - II: Kinematics)

        The Space Telescope Imaging Spectrograph (CCD) was used to make 
observations of the radio-loud elliptical galaxy NGC-3862.  From these 
observations we will measure the black hole masses, determine the nature, 
kinematics, and structure of the central gas disks and obtain a modeled 
upper limit to their mass accretion rates.  A wavelength calibration image 
was also taken.  The observations were completed as planned, and no 
problems were reported.

    1.12 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.

    1.13 Completed 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}.  The 
observations completed nominally.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 10
Successful: 10

  Scheduled Re-acquisitions:  4
Successful:  4

    2.2 FHST Updates:
Scheduled: 27
Successful: 27

    2.3 Operations Notes:

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

        The engineering status buffer limits were adjusted on three 
occasions per ROP DF-18A.

        A TTR was written when a GCMR to change to Mode 1 failed at 
085/2201Z, resulting in 3-minutes, 17-seconds loss of engineering 
data.  Another TTR documented intermittent MA-return data, beginning at 
086/0151Z.  This resulted in a one-minute loss of engineering data.

        After the CoreData Server CCL_ISP process went down on the CCS "A" 
string at 086/0200Z (HSTAR 8135), operations transitioned to the "G" string 
at 086/0235Z.  After a complete re-cycle, operations returned to "A" string 
at 086/0340Z.

        The ephemeris table uplink was performed at 086/0119Z as directed 
by ROP DF-07A.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW