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 (z>1). 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)