HUBBLE SPACE TELESCOPE

  DAILY REPORT #2927

PERIOD COVERED:  0000Z (UTC) 08/01/01 - 0000Z (UTC) 08/02/01

Daily Status Report as of 214/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Thirteen Sets of 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.

    1.2 Completed WF/PC-2 8821 (Cycle 9 CTE Monitor)

        The WF/PC-2 was used to monitor CTE changes during cycle 9.  It is 
expected to determine CTE and zero points by comparison to ground based 
observations of clusters.  The observations completed nominally.

    1.3 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.

    1.4 Completed WF/PC-2 9060 (Photometry of a Statistically Significant 
Sample of Kuiper Belt Objects)

        The WF/PC-2 was used to propel the physical study of KBOs forward 
by performing accurate photometry at V, R, and I on a sample of up to 150 
KBOs.  The sample is made up of objects that will be observed at thermal 
infrared wavelengths by SIRTF and will be used with those data to derive 
the first accurate diameters and albedos for a large sample of KBOs.  The 
observations completed nominally.

    1.5 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.

    1.6 Completed WF/PC-2 8601 (A Snapshot Survey of Probable Nearby Galaxies)

        The WF/PC-2 was used to continue the very successful snapshot 
survey in order to use the high spatial resolution of HST to determine 
whether selected galaxies are nearby on the basis of resolution into stars, 
and the magnitudes and colors of the brightest stars.  There were no 
reported problems.

    1.7 Completed Two Sets of 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.

    1.8 Completed STIS/CCD 9066 (Closing in on the Hydrogen Reionization 
Edge of the Universe)

        The Space Telescope Imaging Spectrograph (CCD) was used in parallel 
constrain the Hydrogen reionization edge in emission that marks the 
transition from a neutral to a fully ionized IGM at a predicted 
redshifts.  The proposal completed uneventfully.

    1.9 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.

    1.10 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.

    1.11 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.

    1.12 Completed Two Sets of STIS/CCD 7912 (STIS Parallel Archive 
Proposal - Nearby Galaxies - Imaging and Spectroscopy)

        The Space Telescope Imaging Spectrograph (CCD) was used to make 
parallel observations of nearby galaxies.  This survey will be useful to 
study the star formation histories, chemical evolution, and distances to 
these galaxies.  These data will be placed immediately into the Hubble Data 
Archive.  The observations were completed as scheduled, and no problems 
were reported.

    1.13 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.

    1.14 Completed Two 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.

    1.15 Completed WF/PC-2 9173 (The Pattern of Heavy Element Abundances in 
a Damped LyAlpha Galaxy)

        The WF/PC-2 was used to observe the quasar PKS 1127-143.  X-ray 
absorption associated with an intervening 21-cm and damped LyAlpha$ 
absorber at z=0.312 in its spectrum has been detected with Chandra.  The 
advantage of the X- ray measurement is that the derived metallicity is 
insensitive to ionization, inclusion of an atom in a molecule, or depletion 
onto grains.  The X-ray absorption is mostly due to oxygen, and the 
abundance agrees with the oxygen abundance of 16-40 lines in a galaxy at 
the redshift of the absorber.  The STIS spectrum will allow measurement 
of  Zn II, an undepleted iron peak element.  Comparison of the oxygen group 
measured in the X-rays with the iron peak nuclei measured will reveal 
whether the absorber has a Pop II, halo-type abundance pattern or a Pop I, 
disk-like abundance pattern.  The proposla completed with no reported 
anomalous activity.

    1.16 Completed WF/PC-2 9104 (A Study of Proplyds and a Protostellar 
Condensation at the Center of M20)

        The WF/PC-2 was used to observe the Trifid nebula {M20} that is a 
well-known prominent optical HII region trisected by bands of obscuring 
dust lanes and excited by an O7.5 star HD 164492A.  Our recent study of 
near-IR ground-based observations of this region at J, H, K and L show all 
seven components of HD 164492 {A to G} identified optically.  Our 
sub-arcsecond radio continuum VLA and ground- based observations of M20 
also show free-free emission from three stellar sources {B, C and D} and a 
bright rim outlining a protostellar condensation {TC1} lying close to the 
O7V star {HD 164492A} at the center of the nebula.  Based on a number of 
strong arguments, these stars have disks associated with them and their 
envelopes are photoionized externally by the UV radiation from the hot 
central star, HD 164492A.  These proposed WFPC2 observations are intended 
to search for neutral protoplanetary disks ``proplyds'', to study the 
optically bright rim of ionized gas associated with TC1 for signs of star 
formation, and to make a detailed subarcsecond determination of extinction 
toward the dust lanes of M20 using HAlpha and 6cm data.  There were no 
reported problems.

    1.17 Completed 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.

    1.18 Completed 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.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 12
Successful: 12

        Per HSTAR 8293, the acquisition at 214/023031Z failed to fine lock 
backup on FGS-1 only when the scan step limit was exceeded on FGS-2.  Three 
proposals, all ocurring during the period of the next report may have been 
affected: STIS 8925 and WF/PC-2 8828.
  Scheduled Re-acquisitions:  4
Successful:  4

    2.2 FHST Updates:
Scheduled: 31
Successful: 30

        The update at 213/181403Z failed.

    2.3 Operations Notes:

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

        Nominal Trim Relay Software Charge Control configuration, from two 
to three batteries, was restored at approximately 213/1255Z since the most 
recent high high sun-time period (days.190-205) was over.  In the orbit day 
period following the flight software patch, the trickle charge was 
initiated as expected, after the CCC K52 relay opened and batteries 1 nad 3 
reached their VTFE cut-off levels.  The CCC 5 K2 V/T Level will be left at 
Level 5 in an attempt to help stabilize battery 5 pressure.  (Nominal 
configuration is K52=Level 4).

        The engineering status buffer limits were adjusted at 213/1815Z per 
ROP DF-18A.

        The NSSC-1 status buffer was dumped at 213/2315Z as directed by ROP 
NS-03.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW