Daily Report #4911

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT #4911

PERIOD COVERED: 5am August 17 - 5am August 18, 2009 (DOY
229/09:00z-230/09:00z)

OBSERVATIONS SCHEDULED

COS/FUV 11492

FUV Sensitivity

This activity confirms COS sensitivity versus wavelength over the entire
observable spectrum for all FUV gratings and central wavelength settings.
Obtain quick look sensitivity visit early in SMOV. Later, after wavelength
calibration is verified, 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 obtained
in Visit 13 using primary standard GD153.) No off aperture- center
observations are performed in this activity (see COS32, program 11490, for
off- center characterizations). Spectra will be obtained to meet a Poisson
S/N criterion of ~30 per sensitivity extraction bin or higher; substantially
higher S/N characterization will be utilized in routine Cycle 17
calibration.

COS/NUV/FUV 11486

COS FUV Target Acquisition Algorithm Verification

Verify the ability of the COS FSW to place an isolated point source at the
center of the aperture, both for the BOA and PSA, using dispersed light from
the object using the FUV gratings. The various options for target centering
should be exercised and shown to work properly. This test is for
acquisitions in dispersed-light mode only. This program is modeled from SMOV
activity summary COS28.

This program should be executed two or more weeks after visit 12 of 11469,
and after the SIAF update, so that we have confirmed that NUV imaging
acquisitions work properly with the BOA.

STIS/CCD 11567

Boron Abundances in Rapidly Rotating Early-B Stars

Models of rotation in early-B stars predict that rotationally driven mixing
should deplete surface boron abundances during the main-sequence lifetime of
many stars. However, recent work has shown that many boron depleted stars
are intrinsically slow rotators for which models predict no depletion should
have occurred, while observations of nitrogen in some more rapidly rotating
stars show less mixing than the models predict. Boron can provide unique
information on the earliest stages of mixing in B stars, but previous
surveys have been biased towards narrow-lined stars because of the
difficulty in measuring boron abundances in rapidly rotating stars.The two
targets observed as part of our Cycle 13 SNAP program 10175, just before
STIS failed, demonstrate that it is possible to make useful boron abundance
measurements for early-B stars with Vsin(i) above 100 km/s. We propose to
extend that survey to a large enough sample of stars to allow statistically
significant tests of models of rotational mixing in early-B stars.

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.

STIS/CCD 11851

Slit Wheel Repeatability

Test the repeatibility of the slit wheel by taking a sequence of comparison
lamp spectra with grating G230MB (2697) and the three smallest long slits
(52X0.2, 52X0.1, and 52X0.05). This is a clone of Cycle 12 Program 10029.

STIS/MA1 11861

MAMA FUV Flats

This program will obtain FUV-MAMA observations of the STIS internal Krypton
lamp to construct an FUV flat applicable to all FUV modes.

STIS/MA2 11862

MAMA NUV Flats

This program will obtain NUV-MAMA observations of the STIS internal
Deuterium lamp to construct an NUV flat applicable to all NUV modes.

STIS20 11402

STIS-20 NUV MAMA Dark Monitor

The STIS NUV-MAMA dark current is dominated by a phosphorescent glow from
the detector window. Meta-stable states in this window are populated by
cosmic ray impacts, which, days later, can be thermally excited to an
unstable state from which they decay, emitting a UV photon. The equilibrium
population of these meta-stable states is larger at lower temperatures; so
warming up the detector from its cold safing will lead to a large, but
temporary, increase in the dark current.

To monitor the decay of this glow, and to determine the equilibrium dark
current for Cycle 17, four 1380s NUV-MAMA ACCUM mode darks should be taken
each week during the SMOV period. Once the observed dark current has reached
an approximate equilibrium with the mean detector temperature, the frequency
of this monitor can be reduced to one pair of darks per week.

WFC3 11428

D2 Calibration Lamp Test

This proposal verifies the health and performance of the calsystem deuterium
lamp and assesses the status of the major UV filters by taking a full set of
internal flatfields. A total of three nominal and one short exposure are
obtained for each filter in order to establish an initial baseline of
flatfield data as well as to confirm lamp repeatability and provide a
contamination check. Additional iterations of D2 internal flatfields will be
taken as part of WFC-19, UVIS Internal Flats (proposal 11432).

This proposal corresponds to SMOV ID WFC3-15. It should not be run until
after the successful completion of WFC-06, the UVIS detector functional test
(proposal 11419) and WFC-11, the initial UVIS alignment (proposal 11424).

WFC3 11447

WFC3 IR Dark Current, Readnoise, and Background

This proposal obtains full-frame, four-amp readout images.
Un-illuminated internals are taken at regularly spaced intervals
throughout SMOV in order to assess and monitor readnoise and dark
current (of both light-sensitive pixels and reference pixels), and bad
(warm, hot, dead, variable) pixels. In addition, externals aimed at
fields with sparse stellar density are taken to measure diffuse
background light.

This program corresponds to WFC3-34.

WFC3/IR 11915

IR Internal Flat Fields

This program is the same as 11433 (SMOV) and depends on the completion of
the IR initial alignment (program 11425). This version contains three
instances of 37 internal orbits; to be scheduled early, middle, and near the
end of Cycle 17, in order to use the entire 110-orbit allocation.

In this test, we will study the stability and structure of the IR channel
flat field images through all filter elements in the WFC3-IR channel. Flats
will be monitored, i.e. to capture any temporal trends in the flat fields,
and delta flats produced. High signal observations will provide a map of the
pixel-to-pixel flat field structure, as well as identify the positions of
any dust particles.

WFC3/IR 11937

IR Grism Wavelength Calibration

This program will determine the wavelength calibration for the IR G102 and
G141 grisms as a function of spatial position within the field of view. The
planetary nebula Vy2-2 will be observed in a 9-point pattern in the IR field
of view, which will provide FoV-dependent dispersion maps for the G102 and
G141 grisms.

WFC3/UVI 11657

The Population of Compact Planetary Nebulae in the Galactic Disk

We propose to secure narrow- and broad-band images of compact planetary
nebulae (PNe) in the Galactic Disk to study the missing link of the early
phases of post-AGB evolution. Ejected AGB envelopes become PNe when the gas
is ionized. PNe expand, and, when large enough, can be studied in detail
from the ground. In the interim, only the HST capabilities can resolve their
size, morphology, and central stars. Our proposed observations will be the
basis for a systematic study of the onset of morphology. Dust properties of
the proposed targets will be available through approved Spitzer/IRS spectra,
and so will the abundances of the alpha-elements. We will be able thus to
explore the interconnection of morphology, dust grains, stellar evolution,
and populations. The target selection is suitable to explore the nebular and
stellar properties across the Galactic Disk, and to set constraints on the
galactic evolutionary models through the analysis of metallicity and
population gradients.

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 11907

UVIS Cycle 17 Contamination Monitor

The UV throughput of WFC3 during Cycle 17 is monitored via weekly standard
star observations in a subset of key filters covering 200-600nm and F606W,
F814W as controls on the red end. The data will provide a measure of
throughput levels as a function of time and wavelength, allowing for
detection of the presence of possible contaminants.

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 06 06
FGS REAcq 10 10
OBAD with Maneuver 05 05

SIGNIFICANT EVENTS: (None)