Daily Report #4926

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #4926

PERIOD COVERED: 5am September 8 - 5am September 9, 2009 (DOY 251/09:00z-252/09:00z)

OBSERVATIONS SCHEDULED

ACS/SBC 12003

The Impact Event on Jupiter in 2009

An image of Jupiter taken on 19 July 2009 at 15 UT showed an anomalous
feature in the southern hemisphere. The world-wide community responded
with observations, and the subsequent data strongly suggest that an
impact occurred during the 8 hours preceding that discovery image. The
Hubble Space Telescope is the only facility that can provide
high-spatial-resolution visible images of the impact site, and the
only facility that can provide UV images that show the impactor's
effect on the Jovian stratosphere. We request 7 orbits of HST time to
characterize this rare event. We hope that two orbits can be as soon
as is feasible (Wednesday or Thursday, 22 or 23 July). We would like a
second pair several days later, perhaps Saturday. We request another 2
orbits the following week. The last, seventh, orbit can be several
weeks or a month later.

COS/FUV 11493

COS FUV Structural and Thermal Stability

The goal of this program is to measure OTA-COS pointing jitter or
drifts, over timescales of minutes to hours. In particular, our
priorities are to test the level of OSM1 drift, thermal day-night
transitions and orbital 'breathing'. Pointing-related thermal offsets
with their related drifts during thermal settling will be overlaid
upon the signatures of the other components of positional change.
Three different instrumental configurations/transitions will be
tested: NUV and FUV spectroscopy, and NUV imaging using Mirror A. All
with the PSA. No FP-POS motions, nor grating changes will be made
during the spectroscopy in order to limit the variables contributing
to any changes in position of the spectra.

ID: COS 20 (Proposal 11480) & COS 35 (Proposal 11493) This is the FUV
portion of this experiment. It was initially estimated to be a 3-orbit
program, but has been extended to 5 orbits in order to improve the
statistics of our measure of the effect of day-night/breathing.

COS/FUV 11897

FUV Spectroscopic Sensitivity Monitoring

The purpose of this proposal is to monitor sensitivity in each FUV
grating mode to detect any changes due to contamination or other
causes.

FGS 11942

Increasing the Accuracy of HST Astrometry with FGS1R

We propose to observe six exoplanetary system host stars and two
planetary nebulae central stars with FGS1R. All objects have been
previously observed under proposals GO-09233, -09969, -10989, and
-11210. These observations will significantly extend the time
baseline, permitting improvements in the determination of proper
motion. This systematic motion must be removed to get at the
perturbation of interest, either due to exoplanetary companions or the
orbital motion of the Earth (parallax). In most cases the perturbation
orbits will also improve. We improve either companion mass or PN
parallax. For one target, GJ 876, theoretical dynamical modelers have
proposed an inclination closer to 50 degrees, while FGS3 measurements
indicated an inclination closer to 84 degrees. These new data, once
combined with our older FGS3 data, will permit an independent
remeasurement of the inclination of the outermost companion, and a re-
evaluation of widely used dynamical algorithms.

STIS/CCD 11844

CCD Dark Monitor Part 1

The purpose of this proposal is to monitor the darks for the STIS CCD.

STIS/CCD 11846

CCD Bias Monitor-Part 1

The purpose of this proposal is 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.

STIS/CCD 11849

STIS CCD Hot Pixel Annealing

This purpose of this activity is to repair radiation induced hot pixel
damage to the STIS CCD by warming the CCD to the ambient instrument
temperature and annealing radiation-damaged pixels.

Radiation damage creates hot pixels in the STIS CCD Detector. Many of
these hot pixels can be repaired by warming the CCD from its normal
operating temperature near - 83 deg. C to the ambient instrument
temperature (~ +5 deg. C) for several hours. The number of hot pixels
repaired is a function of annealing temperature. The effectiveness of
the CCD hot pixel annealing process is assessed by measuring the dark
current behavior before and after annealing and by searching for any
window contamination effects.

WFC3/IR 11719

A Calibration Database for Stellar Models of Asymptotic Giant Branch
Stars

Studies of galaxy formation and evolution rely increasingly on the
interpretation and modeling of near-infrared observations. At these
wavelengths, the brightest stars are intermediate mass asymptotic
giant branch (AGB) stars. These stars can contribute nearly 50% of the
integrated luminosity at near infrared and even optical wavelengths,
particularly for the younger stellar populations characteristic of
high-redshift galaxies (z1). AGB stars are also significant sources
of dust and heavy elements. Accurate modeling of AGB stars is
therefore of the utmost importance.

The primary limitation facing current models is the lack of useful
calibration data. Current models are tuned to match the properties of
the AGB population in the Magellanic Clouds, and thus have only been
calibrated in a very narrow range of sub- solar metallicities.
Preliminary observations already suggest that the models are
overestimating AGB lifetimes by factors of 2-3 at lower metallicities.
At higher (solar) metallicities, there are no appropriate observations
for calibrating the models.

We propose a WFC3/IR SNAP survey of nearby galaxies to create a large
database of AGB populations spanning the full range of metallicities
and star formation histories. Because of their intrinsically red
colors and dusty circumstellar envelopes, tracking the numbers and
bolometric fluxes of AGB stars requires the NIR observations we
propose here. The resulting observations of nearby galaxies with deep
ACS imaging offer the opportunity to obtain large (100-1000's)
complete samples of AGB stars at a single distance, in systems with
well-constrained star formation histories and metallicities.

WFC3/IR/S/C 11929

IR Dark Current Monitor

Analyses of ground test data showed that dark current signals are more
reliably removed from science data using darks taken with the same
exposure sequences as the science data, than with a single dark
current image scaled by desired exposure time. Therefore, dark current
images must be collected using all sample sequences that will be used
in science observations. These observations will be used to monitor
changes in the dark current of the WFC3-IR channel on a day-to-day
basis, and to build calibration dark current ramps for each of the
sample sequences to be used by GOs in Cycle 17. For each sample
sequence/array size combination, a median ramp will be created and
delivered to the calibration database system (CDBS).

WFC3/UVIS 11565

A Search for Astrometric Companions to Very Low-Mass, Population II
Stars

We propose to carry out a Snapshot search for astrometric companions
in a subsample of very low-mass, halo subdwarfs identified within 120
parsecs of the Sun. These ultra-cool M subdwarfs are local
representatives of the lowest-mass H burning objects from the Galactic
Population II. The expected 3-4 astrometric doubles that will be
discovered will be invaluable in that they will be the first systems
from which gravitational masses of metal-poor stars at the bottom of
the main sequence can be directly measured.

WFC3/UVIS 11905

WFC3 UVIS CCD Daily Monitor

The behavior of the WFC3 UVIS CCD will be monitored daily with a set
of full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K
subarray biases are acquired at less frequent intervals throughout the
cycle to support subarray science observations. The internals from
this proposal, along with those from the anneal procedure (Proposal
11909), will be used to generate the necessary superbias and superdark
reference files for the calibration pipeline (CDBS).

WFC3/UVIS 11908

Cycle 17: UVIS Bowtie Monitor

Ground testing revealed an intermittent hysteresis type effect in the
UVIS detector (both CCDs) at the level of ~1%, lasting hours to days.
Initially found via an unexpected bowtie-shaped feature in flatfield
ratios, subsequent lab tests on similar e2v devices have since shown
that it is also present as simply an overall offset across the entire
CCD, i.e., a QE offset without any discernable pattern. These lab
tests have further revealed that overexposing the detector to count
levels several times full well fills the traps and effectively
neutralizes the bowtie. Each visit in this proposal acquires a set of
three 3x3 binned internal flatfields: the first unsaturated image will
be used to detect any bowtie, the second, highly exposed image will
neutralize the bowtie if it is present, and the final image will allow
for verification that the bowtie is gone.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.)

HSTARS: (None)

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSAcq 4 4
FGS REAcq 7 7
OBAD with Maneuver 3 3

SIGNIFICANT EVENTS: (None)