HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT      #4909

PERIOD COVERED: 5am August 13 - 5am August 14, 2009 (DOY 225/09:00z-226/09:00z)

OBSERVATIONS SCHEDULED

COS 11473

COS NUV Imaging Performance Verification

This activity is designed to verify the performance of the COS/NUV

imaging mode. In particular, the PSF quality will be assessed and the

plate scale will be measured. The throughput of the MIRRORA with both

the PSA and BOA will be fully calibrated by observing an appropriate HST

flux standard star, and will be characterized as a function of location

within the aperture by moving the star from the center to various

positions with a grid pattern. The relative throughput of MIRRORA vs

MIRRORB will also be evaluated in the center of both the PSA and BOA.

This activity will be structured in a way that will also allow for

testing of the drift following the OSM motion in imaging mode and for

testing of the image stability within an orbit and over several orbits.

COS/NUV 11479

COS NUV Spectroscopic Sensitivity

This activity confirms COS sensitivity versus wavelength over the entire

observable spectrum for all NUV gratings and central wavelength

settings. Perform a precise-centering acquisition and observe an

appropriate HST flux standard star (chosen from the HST prime standard

and FASTEX lists) with the PSA. A limited BOA characterization is also

obtained (see also program 11476, activity COS16). A quick spot check of

the sensitivities with the PSA is also executed immediately after the

NUV alignment (but at least 7 days after that). No off aperture-center

observations are performed in this activity (see program 11477, activity

COS17, for off-center characterizations). Spectra will be obtained to

meet a Poisson S/N criterion of 20 per resolution element in the central

wavelength of the setting; higher S/N characterization will be utilized

in routine Cycle 17 calibration.

STIS/CCD 11844

CCD Dark Monitor Part 1

Monitor the darks for the STIS CCD.

STIS/CCD 11846

CCD Bias Monitor-Part 1

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.

WFC3 11446

WFC3 UVIS Dark Current, Readnoise, and CTE

This proposal obtains full-frame, four-amp readout bias and dark frames

at regularly-spaced intervals throughout SMOV in order to assess and

monitor dark current, bad (warm, hot, dead) pixels, and readnoise. In

addition, a set of internals using the WFC3 calsystem are taken to

provide a baseline CTE measurement. WFC3-33

WFC3 11451

IR Photometric Zero Points

This proposal obtains the photometric zero points in all 15 WFC3/IR

filters using two stars with distinct temperatures (a hot DA white dwarf

and a solar analog). The observations are repeated at intervals of 1

day, 7 days, and 30 days, to monitor photometric stability in all

filters.

WFC3/UVI 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/UVI 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 (11909), will be

used to generate the necessary superbias and superdark reference files

for the calibration pipeline (CDBS).

WFC3/UVI 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               05                 05                

FGS REAcq               11                 11               

OBAD with Maneuver 04                 04                

SIGNIFICANT EVENTS: (None)