HUBBLE SPACE TELESCOPE

   DAILY REPORT #2598

PERIOD COVERED:  0000Z (UTC) 04/07/00 - 0000Z (UTC) 04/10/00

Daily Status Report as of 101/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed WF/PC-2 8114 (Fundamental Problems in Plasma Astrophysics)

        The WF/PC-2 was used to observe NGC 7009 which has become the 
standard-bearer for a growing body of work that finds nebular abundances 
derived from recombination lines are up to factors of 5--15 larger than 
those obtained from the optical/UV collisionally excited lines.  These can 
be forced into agreement at the higher value if large unexplained 
temperature fluctuations {t^2} exist. STIS long-slit observations will 
allow us to study the line-of-sight t^2 in addition to plane-of-the-sky 
variations, within the slit areas, thereby creating 3-dimensional t^2 
information.  As described in the previous report and HSTAR 7570, the 
acquisition for this proposal defaulted to fine lock backup on one FGS 
only, possibly affecting five observations.  Otherwise, the proposal 
completed nominally with no further problems being reported.

    1.2 Completed Four Sets of STIS/CCD 8439 (Bias Monitor-Part 2 C8)

        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.  As described in the previous report and HSTAR 7570, the 
acquisition for the first iteration of this proposal defaulted to fine lock 
backup on one FGS only, possibly affecting five observations.  Otherwise, 
the proposal completed with no further problems.

    1.3 Completed Four Sets of STIS/CCD 8437 (Dark Monitor-Part 2 C8)

        The Space Telescope Imaging Spectrograph (CCD) was used to monitor 
the darks.  The proposal completed nominally.

    1.4 Completed Eight Sets of WF/PC-2 8460 (Cycle 8 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 observations completed with no reported problems.

    1.5 Completed Four Sets of WF/PC-2 8448 (Cycle 8 INTFLAT Sweeps, 
VISFLAT Mini-Sweep, and Linearity Test)

         The WFPC2 was used to monitor the pixel to pixel flatfield 
response and the VISFLAT lamp degradation, as well as detect any possible 
changes due to contamination.  As described in 2.1 and HSTAR 7571, the 
acquisition for the third iteration of this proposal failed, affecting 10 
observations.  Otherwise, the observations completed nominally.

    1.6 Completed Two Sets of STIS/CCD 8217 (Tests of Stellar Models Using 
Four Extremely Massive Spectroscopic Binaries in the R136 Cluster)

        The Space Telescope Imaging Spectrograph (CCD) was used to observe 
four non-interacting double-lined spectroscopic binaries discovered in the 
R136 cluster by the Cycle 6 FOS spectroscopy.  The proposal completed 
nominally.

    1.7 Completed WF/PC-2 8059 (POMS Test Proposal: Targeted Parallel 
Archive Proposal)

        The WF/PC-2 was used to observe the parallel opportunities 
available in the neighborhood of bright galaxies are treated in a slightly 
different way from the normal pure parallels.  Local Group galaxies offer 
the opportunity for a closer look at young stellar 
populations.  Narrow-band images in F656N can be used both to identify 
young stars via their emission lines, and to map the gas distribution in 
star-forming regions.  The observations completed nominally.

    1.8 Completed Three Sets of STIS/CCD 8115 (Stellar Seismology from 
Space: From the Sun to the Stars)

        The Space Telescope Imaging Spectrograph (CCD) was used to obtain 
the first unambiguous detection of acoustic oscillations in a solar-type 
star other than the Sun.  Numerous ground-based asteroseismology 
experiments have failed to produce a definitive signal partly because 
scintillation in the Earth's atmosphere limits photometric precision.  From 
its vantage point in space, HST can reliably measure mode frequencies and 
dominant splittings with an accuracy of 3 MuHz in only 15 CVZ orbits.  The 
observations completed with no reported anomalies.

    1.9 Completed Nine Sets of WF/PC-2 8090 (POMS Test Proposal: WF-II 
Parallel Archive Proposal Continuation)

        The WF/PC-2 was used in the parallel mode to make some low galactic 
latitude archive observations.  The program will be used to take parallel 
images of random areas of the sky.  The observations were executed as 
scheduled, and no anomalies were noted.

    1.10 Completed Seven Sets of STIS/CCD 8549 (POMS Test Proposal: 
Non-Scripted Parallel Proposal Continuation I)

        The Space Telescope Imaging Spectrograph (CCD) was used to make low 
galactic latitude, non-scripted parallel observations as part of a POMS 
test proposal.  The observations were completed as planned, and no 
anomalies were reported.

    1.11 Completed WF/PC-2 8100 (Calibration of Nearby Type Ia Supernovae 
as Standard Candles: The Next Step)

        The WF/PC-2 was used to continue the calibration experiment for M{ 
max} of type Ia supernovae {SNe Ia} by determining Cepheid distances to 
their parent galaxies.  The proposal completed nominally.

    1.12 Completed STIS/CCD 8647 (Black Hole Accretion Outbursts In Soft X- 
Ray Transients)

        The Space Telescope Imaging Spectrograph (CCD) was used to make UV 
observations of soft X-ray transient {SXT} XTE-J1118 . This is part of an 
extensive multiwavelength target of opportunity campaign to monitor newly 
discovered SXTs in outburst and throughout the subsequent decline.  Recent 
work establishes that a high proportion of SXTs harbor black holes, so 
these observations provide an unrivalled opportunity to obtain high quality 
data from an accreting black hole.  UV data is a keystone of this 
multiwavelength campaign because the disk regions of interest radiate 
predominantly in the UV.  Emission lines will give the ability to probe the 
kinematics of the inner disk region.  Tthe relative strengths of the 
reprocessed X-ray flux emitted in the UV will be examined, and the UV flux 
generated by viscous heating in the accretion flow.  Multiwavelength 
observations will probe the physics of the accretion flow throughout the 
outburst.  The observations will yield detailed quantitative tests of the 
models for SXT outbursts.  The new STIS/MAMA capability to perform UV 
spectroscopy with 125 microsecond time resolution will be exploited.  A 
proven HST/RXTE echo-mapping experiment will measure the size of the 
reprocessing regions in the accretion disk, and thus probe morphology 
changes as the decline proceeds.  It is unknown what rapid UV variability 
may be found.  Recent RXTE discoveries suggest this may prove a rich source 
of information on the dynamics close to the event horizon.  The 
observations completed with no reported problems.

    1.13 Completed STIS/CCD 8202 (Bright Quasar Close Lensing Search)

        The Space Telescope Imaging Spectrograph (CCD) was to be used to 
make observations of HCLQ1130+4 and HCLQ2220-2 as part of a second 
generation survey to search for bright lensing quasars.  As described in 
2.1 and HSTAR 7571, the acquisition for this proposal failed, affecting two 
observations.

    1.14 Completed Two Sets of STIS/CCD 8228 (The Black Hole Versus Bulge 
Mass Relationship in Spiral Galaxies)

        The Space Telescope Imaging Spectrograph (CCD) was used to make 
observations of the galaxies NGC-5054 and NGC-7314 in order to study the 
black hole versus bulge mass relationship in spiral galaxies.  Wavelength 
calibration images were also taken.  The observations were executed as 
scheduled, and no anomalies were noted.

    1.15 Completed Three Sets of WF/PC-2 8457 (UV Earth Flats)

        The WF/PC-2 was used to obtain a series of Ultraviolet Earth 
flats.  The observations were completed with no reported problems.

    1.16 Completed WF/PC-2 8322 (The Distance to NGC 2841: Improving the TF 
Calibration and Definitively Testing MOND)

        The WF/PC-2 was used to measure a distance to the spiral galaxy NGC 
2841 using Cepheid variables.  NGC 2841 provides a unique opportunity to 
simultaneously probe three separate phenomenon in extragalactic astronomy: 
1} It will provide the highest rotational velocity data point for the 
Cepheid based calibration of the I-band Tully-Fisher relation and thus will 
firmly determine if this relation experiences curvature or remains linear 
all the way out to high rotational velocities. 2} It has hosted two SN Ia 
events; both of which have good photometry {1957A and 1972R}- this 
significantly adds to the number of calibrators for the SN Ia distance 
scale; 3} If its distance can be shown to be significantly less than 19.5 
MPC, then MOND can be definitively ruled out because NGC 2841 will require 
a value of a_o substantially in excess of the empirically determined 
"universal" value.   The observations completed nominally.

    1.17 Completed WF/PC-2 8230 (Snapshot Survey of Dynamically Close 
Galaxy Pairs from z=0.1 to z=0.5)

        The WF/PC-2 was used to make snapshot survey observations of 
galactic cluster Gal-Clus-2.  This is to obtain snapshot images of a large, 
well-defined, and dynamically selected sample of close galaxy pairs at 
moderate redshift.  The observations were executed as scheduled, and no 
anomalies were noted.

    1.18 Completed WF/PC-2 8059 (POMS Test Proposal: Targeted Parallel 
Archive Proposal)

        The WF/PC-2 was used to observe the parallel opportunities 
available in the neighborhood of bright galaxies are treated in a slightly 
different way from the normal pure parallels.  Local Group galaxies offer 
the opportunity for a closer look at young stellar 
populations.  Narrow-band images in F656N can be used both to identify 
young stars via their emission lines, and to map the gas distribution in 
star-forming regions.  The observations completed nominally.

    1.19 Completed STIS/MA1 8426 (Cycle 8 MAMA Dark Measurements)

        The Space Telescope Imaging Spectrograph (MA1) was used to make a 
routine Cycle-8 MAMA dark noise calibration measurement.  This proposal 
will provide the primary means of checking on the health of the MAMA 
detectors.  This is done through frequent monitoring of the background 
count rate.  The observations were completed as planned, and no problems 
were reported.

    1.20 Completed STIS/CCD 8176 (Confirmation and Characterization of 
Brown Dwarfs and Giant Planets from NICMOS 7226/7227)

        The Space Telescope Imaging Spectrograph (CCD) was used to make 
confirmation and characterization observations of object TWA6B.  This is a 
continuation of NICMOS 7226/7227 using the STIS.  A systematic search for 
giant planet and brown dwarf companions to stars in the solar neighborhood 
was the cornerstone of the NICMOS IDT's Environments of Nearby Stars {EONS} 
program.  The observations were completed as planned, and no anomalies were 
reported.

    1.21 Completed WF/PC-2 8544 (POMS Test Proposal: WFII Backup Parallel 
Archive Proposal II)

        The WF/PC-2 was used to execute a POMS test proposal which was 
designed to simulate scientific plans.  No problems were encountered.

    1.22 Completed Three Sets of STIS/CCD 8419 (Deep Corongraphic PSF 
Calibration of STIS)

        The Space Telescope Imaging Spectrograph (CCD) was used to make 
observations of standard star HD141653 in order to do a deep coronographic 
Point Spread Function (PSF) calibration observations. This is to acquire a 
set of deep, coronographic images of isolated, point source stars with STIS 
for the purpose of correcting coronographic science observations for 
residual scattered light from the occulted object.  The observations were 
completed as planned, and no anomalies were reported.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 20
Successful: 19

       As described in HSTAR 7571, the acquisition at 099/210529Z failed to 
RGA control when the scan step limit was exceeded on FGS-2.  A subsequent 
map showed vehicle axis errors of 1.8, 2.6, and 12.7.  The proposals 
described in 1.5 and 1.13 were affected.
  Scheduled Re-acquisitions: 20
Successful: 20

    2.2 FHST Updates:
Scheduled: 44
Successful: 44

    2.3 Operations Notes:

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

        SSA transmitter #1 was turned on and off twice, at 098/1946Z and at 
098/2202Z, per ROP IC-2.

        Using ROP IC-1, transmitter #1 was turned on and off at 100/1803Z.

        A TTR was written for a five-minute, 52-second period of 
non-recoverable real-time data loss.

        A STIS EMC retry occurred at 100/214223Z.

        The NICMOS temperature sensor for detector #2 was enabled at 101/0745Z.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW