HUBBLE SPACE TELESCOPE

  DAILY REPORT #2859

PERIOD COVERED:  0000Z (UTC) 04/25/01 - 0000Z (UTC) 04/26/01

Daily Status Report as of 116/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Two 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.

    1.2 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.

    1.3 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.

    1.4 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 Six 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}.  The 
observations completed nominally.

    1.6 Completed Five 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.

    1.7 Completed Three Sets of FGS/1 8731 (A High Angular Resolution 
Survey of the Most Massive Stars in the SMC)

        Fine Guidance Sensor #1 was used to conduct high angular resolution 
observations of some of the SMC's hottest and most luminous objects by 
conducting a comprehensive survey of nearly every spectral type in the 
upper portion of the HR diagram.  Binary or multiple star systems will be 
detected down to an unprecedented level, more than one order of magnitude 
better than possible with WFPC2.  The targets selected include a 
representative list of normal Main Sequence O-stars and their evolved 
descendents, namely supergiants, hypergiants, LBVs, and WRs, many of which 
have been previously observed by HST's spectrometers for purposes of 
cosmological calibrations.  The observations completed, and no problems 
were reported.

    1.8 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.

    1.9 Completed STIS/CCD 9246 (POMS Test Proposal: Non-scripted Parallel 
Proposal Continuation IV)

        The Space Telescope Imaging Spectrograph (CCD) 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.

    1.10 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 8702 (The Most Elusive Nuclei of LMC Planetary 
Nebulae)

        The WF/PC-2 was used to carry out a SNAPSHOT survey of the faintest 
nuclei of planetary nebulae {PNe} in the LMC.  This program will be a 
crucial follow-on to a Cycle 8 SNAPSHOT of LMC Pne.  In thisa case the plan 
is to observe the faintest or most obscured nuclei to determine their 
evolutionary state to an accuracy not possible in the Galaxy.  These 
faintest central stars are predicted to be among the most massive nuclei, 
and owing to the typically advanced age of the surrounding nebulae, are the 
most sensitive discriminants for validating the post-AGB evolution 
timescales predicted by theory.  The observations completed with no 
reported problems.

    1.12 Completed WF/PC-2 8581 (A Search For Low-Mass Companions To 
Ultracool Dwarfs)

        The WF/PC-2 was used to search for very low-mass {VLM} companions 
to a complete sample of 120 late-M and L dwarfs, drawn mainly from the 
2MASS and SDSS surveys.  The primary goal is to determine the multiplicity 
of M < 0.1 M_odot dwarfs.  In particular, we aim to identify binary systems 
suitable for long-term astrometric monitoring and mass measurement, and 
systems with cool, sub-1000K companions.  The proposal completed with no 
reported problems.

    1.13 Completed 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.

    1.14 Completed WF/PC-2 8682 (A Snapshot Study of 0bservational Cosmology)

        The WF/PC-2 was used to examine the observational constraints on 
the cosmic star formation history that is currently among the most active 
fields in observational cosmology.  The most widely used tracer of the 
co-moving volume-averaged star formation rate {SFR} is the UV luminosity 
density, which early results found to peak at z~1- 2.  The apparent 
identification of the primary epoch of metal production and star formation 
in the Universe led to intense theoretical and observational 
interest.  Nevertheless, and remarkably for such a fundamental observation, 
little is known about the history of star formation in the Universe beyond 
its global average.  There were no reported anomalies.

    1.15 Completed STIS/CCD/MA1 8566 (High Resolution UV/X-Ray Spectroscopy 
of SMC X-1)

        The Space Telescope Imaging Spectrograph (CCD and MA1) was used to 
perform simultaneous observations of the X-ray pulsar SMC X-1 and its B0 
companion SK160 with Chandra and ground-based optical telescopes.  The 
proposer will search for correlation between orbital phase and "bleaching'' 
of important P Cygni lines by X-ray photoionization, and will model the 
simultaneous X-ray, ultraviolet, and optical continuum emission at 
different phases of the superorbital period to measure changes in mass 
accretion rate, disk structure, and disk size.  The proposal completed with 
no reported problems.

    1.16 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.

    1.17 Completed WF/PC-2 8602 (A Snapshot Survey of the Sites of Recent, 
Nearby Supernovae)

        The WF/PC-2 was used to conduct a snapshot survey in V and I of the 
sites of the nearby SNe, which have precisely known positions, to obtain 
high-resolution information on their local environment.  The proposal 
completed with no reported problems.

    1.18  Completed STIS/CCD/MA1 8693 (Interstellar Boron & Oxygen 
Abundances in the Cep OB2 Association: Probing)

        The Space Telescope Imaging Spectrograph (CCD and MA1) was used to 
investigate a specific nuclear process associated with core-collapse 
supernovae that involves the inelastic scattering of neutrinos {produced as 
a result of the core collapse} off of abundant nuclei in the outer layers 
of the dying star.  Two relatively low-abundance elements, boron and 
fluorine, have been suggested to owe some uncertain fraction of their 
cosmic abundances to this process.  In the case of boron, the dominant 
isotope is ^11B, and neutrinos interacting with ^12C can lead to its 
synthesis.  Fluorine-19 is the only stable F isotope and it can be produced 
by neutrino scattering, removing a proton from ^20Ne.  Competing processes 
can also synthesyze these elements: cosmic-ray spallation reactions for B 
and shell He-burning in AGB stars for F.  In order to gauge the importance 
of neutrino nucleosynthesis in the chemical evolution of the Galaxy, we 
will determine interstellar B and O abundances in the gas associated with 
the Cep OB2 association {using the B II 1362Angstrom and O I 1356Angstrom 
lines}.  These results will be combined with observations of interstellar F 
I along the same lines-of-sight obtained with FUSE {fluorine can only be 
compared directly to boron using interstellar lines and interstellar F is 
only observable with FUSE}.  The derived F/O and F/B ratios in Cep OB2 will 
allow us to determine the relative importance of neutrino nucleosynthesis 
to the origins of B and F.  The proposal completed with no reported problems.

    1.19 Completed STIS/CCD/MA1 8956 (Pre-SM Calibration)

        The Space Telescope Imaging Spectrograph (CCD and MA1) was used in 
an exercise to prepare for the SMOV-3B program.  Prior to SMOV3B, one 
iteration of proposal 8960 {Jitter Test} for WD 2126+734 will be 
performed.  Also one iteration of 8961 {End of BEA Test} for each new flux 
standard {WD 2126+734, WD 0320-539, WD 0710+741, and WD 0214+568} needed to 
completely cover all possible Bright Earth Avoidance {BEA} dates will be 
exercised.  Finally, one extra standard is added {WD 1407-475} to fill the 
gap around June when WD 0214+568 is too close to the Sun.  This iteration 
of the proposal completed with no reported problems.

2.0 FLIGHT OPERATIONS SUMMARY:

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

  Scheduled Re-acquisitions:  4
Successful:  4

    2.2 FHST Updates:
Scheduled: 28
Successful: 28

    2.3 Operations Notes:

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

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW