HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT      #4921

PERIOD COVERED: 5am August 31 - 5am September 1, 2009 (DOY 243/09:00z-244/09:00z)

OBSERVATIONS SCHEDULED

ACS/WFC3 11465

ACS CCD Monitoring and Calibration for WFC3

This program is a smaller version of our routine CCD monitoring program,

designed to run throughout SMOV, after which our regular Cycle 17 CAL

proposal will begin. This program obtains the bias and dark frames

needed to generate reference files for calibrating science data, and

allows us to monitor detector noise and the growth of hot pixels.

ACS/WFC3 11879

CCD Daily Monitor (Part 1)

This program comprises basic tests for measuring the read noise and dark

current of the ACS WFC and for tracking the growth of hot pixels. The

recorded frames are used to create bias and dark reference images for

science data reduction and calibration. This program will be executed

four days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To

facilitate scheduling, this program is split into three proposals. This

proposal covers 352 orbits (22 weeks) from 31 August 2009 to 31 January

2010.

ACS/WFC3 11882

CCD Hot Pixel Annealing

All the data for this program is acquired using internal targets (lamps)

only, so all of the exposures should be taken during Earth occultation

time (but not during SAA passages). This program emulates the ACS

pre-flight ground calibration and post-launch SMOV testing (program

8948), so that results from each epoch can be directly compared.

Extended Pixel Edge Response (EPER) and First Pixel Response (FPR) data

will be obtained over a range of signal levels for the Wide Field

Channel (WFC). The High Resolution Channel (HRC) visits have been

removed since it could not be repaired during SM4.

COS/FUV 11488

Internal FUV Wavelength Verification

This program will be executed after the uplink of the OSM1 position

updates derived from the determination of the wavelength-scale zero

points and desired spectral ranges for each grating in Activity COS29

(Program 11487 - COS FUV Internal/External Wavelength Scales). This

program will verify that the operational spectral ranges for each

grating, central wavelength, and FP-POS are those desired. Subsequent to

a successful verification, COS FUV ERO observations that require

accurate wavelength scales (if any) and FUV science can be enabled. An

internal wavelength calibration spectrum using the default PtNe lamp

(lamp 1) with each FUV grating at each central wavelength setting and

each FP-POS position will be obtained for the verification. Additional

exposures and waits between certain exposures will be required to avoid

- and to evaluate - mechanism drifts.

COS/FUV 11489

COS FUV External Spectroscopic Performance - Part 1

The goal of this project is to measure the spectral resolution of

absorption lines for each COS FUV grating. We will acquire science data

at one central wavelength for each grating through both PSA and BOA

apertures. We will evaluate the spectral resolution at offset pointings

characteristic of routine COS observations. The targets chosen for these

observations have sharp absorption lines. First, a target acquisition is

performed to place the target at the center of the aperture. For each

FUV grating we obtain moderately high S/N (~50 per resel counting

statistics) observations at one central wavelength setting with the PSA.

We repeat the sequence of observations at each of four additional

POS-TARG pointings to form a diamond pattern whose vertices are

displaced 0.25 arcsec in either X or Y from the initial pointing. The

purpose of these observations is to characterize the degradation in

spectral resolution due to small positioning errors in the peakup

process. These observations will be obtained in Time-Tag mode and will

utilize Flash=Yes. The total exposure time in all 4 offset positions is

equal to the exposure time at the central position. At each offset

position, there are two exposures, one each at FP positions 3 and 1. For

one grating (G130M) and central wavelength (1291) only we obtain a

Time-Tag exposure with Flash=No to verify auto-wavecal capability. In

addition, on a brighter target, we obtain a single TTag exposure for

each grating with the object centered in the BOA aperture, in order to

measure the spectral resolution in this mode. These spectra will have

S/N=20. Finally, for each grating we obtain one Time-Tag exposure and

one ACCUM exposure with the object centered in the aperture to verify

that the Doppler correction is being properly exectuted on board in

ACCUM mode.

The number of exposures in this program is somewhat greater than is

described in the Activity Summary, but reflects what was intended to be

measured.

This is SMOV Program COS 31.

Implementation Method: Stored commanding

Dependencies: Execute after verification based upon analysis of COS 30

(Internal FUV Wavelength Verification)

Applicable SMOV Requirements: L.10.4.2.3.12.2; L.10.4.2.3.13;

L.10.4.2.1.8.

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 11853

Cycle 17 STIS CCD Imaging Flats

This program periodically monitors the STIS CCD imaging mode flat fields

by using the tungsten lamps.

STIS/CCD/FGS 11848

CCD Read Noise Monitor

This proposal measures the read noise of all the amplifiers (A, B, C, D)

on the STIS CCD using pairs of bias frames. Full-frame and binned

observations are made in both Gain 1 and Gain 4, with binning factors of

1x1, 1x2, 2x1, and 2x2. All exposures are internals. Pairs of visits are

scheduled monthly for the first four months and then bi-monthly after

that.

STIS/MA1 11649

Elucidating the Mystery of the Io Footprint Time Variations

The Io UV footprint (IFP) is an auroral emission on Jupiter consisting

of one or more spots resulting from the electromagnetic interaction

between Io and the Jovian magnetosphere. Recent UV HST observations of

the Jovian aurora raised new issues and put previous interpretations

under question. Dedicated STIS Time-tag observations based on only 3 HST

orbits will help us to directly answer the following questions and test

new hypothesis on the physics driving their associated phenomenon.

The proposed observations will determine whether the previously observed

short timescale (~2 min) variations of the IFP are periodic or burst

events. If the (quasi-) periodicity is established, these constraints

will help us to understand the origin of these variations. These

observations will also clarify the conditions of occurrence of the

unexpected quasi-simultaneous variations of the southern multiple spots

of the IFP. Moreover, we propose to observe the emergence of the

southern leading (or precursor) spot and the possible evolution of its

brightness. These two elements might validate or exclude the recently

proposed idea that cross-hemisphere electron beams or strong non-

linearities of the electromagnetic interaction explain the presence of

the leading and secondary spots.

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/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 (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.

WFC3/UVIS 11924

WFC3/UVIS External and Internal CTE Monitor

CCD detector Charge Transfer Inefficiency (CTI)-induced losses in

photometry and astrometry will be measured using observations of the

rich open cluster NGC6791 and with the EPER (Extended Pixel Edge

Response) method using tungsten lamp flat field exposures. Although we

do not expect to see CTE effects at the outset of Cycle 17, this CTE

monitoring program is the first of a multi-cycle program to monitor and

establish CTE-induced losses with time. We expect to measure CTE effects

with a precision comparable to the ACS measurements.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports

of potential non-nominal performance that will be investigated.)

HSTARS:

11996 - GSAcq(1,2,1) scheduled at 243/13:53:25z - 14:00:56 failed to fine

           lock backup (1,0,1) using FGS-1.

           Observations possibly affected: COS 62 thru 68, Proposal ID# 11489

           Subsequent REAcq(1,2,1) scheduled at 243/15:27:26z resulted in fine

           lock backup (1,0,1) using FGS-1.

           Observations possibly affected: COS 71 thru 76 Proposal ID# 11489,

           ACS 26 Proposal ID# 11879.

HSTARS FOR DAY 226:

11997 - GSAcq(2,1,1) at 226/03:52:43z required two attempts to achieve

           FL-DV on FGS2. FGS2 initially failed a walkdown with scan step limit

           exceeded, but was able to achieve FL-DV on the second try. The

           acquisition was successful.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                       SCHEDULED      SUCCESSFUL 

FGS GSAcq               08                  08                

FGS REAcq               10                  10               

OBAD with Maneuver 07                  07               

SIGNIFICANT EVENTS: (None)