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)