WFC3 SMOV Science Report
26 June 2009
This presentation contains material that is embargoed until after the SM4
ERO press conference. Images/spectra of external (astronomical) objects
may not be altered, distributed, reproduced, published, displayed, or used in
any other way without the consent of the STScI Director or the HST Project.
WFC3 SMOV Activity
Previous 24 hours: Day 176 (June 25,2009)
1) 11543 – IR tungsten lamp cross-check, Visits 1-4
2) 11424 – WFC3 UVIS initial alignment, Visit 1
3) 11808 – UVIS bowtie monitor, Visits 11-12
Up-coming 24 hours: Day 177 (June 26,2009)
1)
2)
3)
4)
5)
11808 – UVIS bowtie monitor, Visits 13-14
11426 – UVIS SMOV contamination monitor, Visits 1,2,3
11446 – WFC3 UVIS dark current, readnoise, and CTE, Visit 1
11447 – WFC3 IR dark current, readnoise, and background, Visit 1
11425 – WFC3 IR Initial Alignment, Visit 1
11421, WFC3 CSM Test
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Activity - Visits 1 & 2 (of 2).
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Objective – Verify the operation and positioning of the WFC3 Channel
Select mechanism via UVIS and IR observations of an external target,
as well as IR internal flats (which use the CSM diffuser paddle).
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Status – Visit 1 obtained 2 UVIS and 1 IR external exposures of the
bright, nearby galaxy M81, which significantly overfills the FOV. Visual
inspection, surface fits to the images, and comparisons with ACS/WFC
images of M81. Visit 2 obtained IR internal F098M and F160W flats.
Ratioed with identical images from 11423 (June 12) and TV3.
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Results
» UVIS and IR images of M81 verify movement of CSM to each
channel position. No indication of any blockage or vignetting of UVIS
and IR fields, indicating that CSM moved to correct positions.
» No indication of CSM repeatability errors from internal flats.
IR Internal Flat Ratios
Embargoed figure - Do not distribute
F098M: 11421 (June 24) vs. 11423 (June 12)
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F098M: 11421 (June 24) vs. TV3
F160W: 11421 (June 24) vs. 11423 (June 12)
Ratios shown with +/- 5% range (0.95 to 1.05)
Bright areas at center of ratios could be due to persistence in 11421 (June 24) images
taken immediately after M81 IR exposure. Extra signal equivalent to ~5 e/sec.
No obvious signs of shifting of any CSM features in ratios.
F098M ratio against 11423 (June 12) image shows dark areas along some edges and
corners that don’t appear in similar F160W ratio, nor do they appear in an F098M ratio
against a TV3 image. Suggests that F098M image from 11423 (June 12) is off-nominal
in some way. Noticed in earlier 11423 SMOV report.
11424- UVIS Initial Alignment
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Activity - Visit 1 of 3: images of open cluster NGC188 in F410M at 5
focus positions
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Objective – Optimize UVIS image quality over field.
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Status – Images analyzed; encircled energy and phase retrieval used to
determine alignment corrections. 18 stars used to sample the field.
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Results
» UVIS (inner, outer) corrector cylinders to be moved (-5,-16) steps;
this is well within our ground based alignment experience range
» UVIS focus stage to be moved -150 steps; also well in range.
» Corrections to be applied via realtime command before visit 2
(Saturday AM)…Ops request specified
» Investigating larger than expected image position travel vs focus
11808 – UVIS bowtie monitor
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Activity – visit 11, Baggett & Borders
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Objective – measure CCD pinning state/provide pinning exposure
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Status – each new visit of bowtie monitor intflats examined via several
methods and compared to previous images.
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Results
» No evidence of bowtie feature in image ratios
» While first post-anneal bowtie visit showed slight structures and
overall level change, ratios since then have been flat to <1%.
» Image ratio from this visit is slightly less flat (~0.2% in amps C/D)
than in previous visit.
11543 - IR tungsten lamp cross-check
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Activity – visits1-4, Baggett
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Objective – primary goal: evaluate lamp status compared default lamp
and ground data. Flatfields also inspected for any changes in filters.
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Status – image statistics, display, ratios with previous data.
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Results
» Lamp output 5-10% higher than in TV3.
» Spare lamp 7-15% brighter than primary lamp, similar to TV3.
» Flatfields appear nominal, with typical features observed in TV3.
» In ratios of on-orbit to TV3 spare lamp intflats, there is a small
region,~70x70pix in outer corner of quadrant 1 (upper left), that is
~1% low in all filters. Another region (50 col x 200 rows) bordering
outside edge of quadrant 2 (lower left) is also ~1% low.
F105W internal flat
Embargoed figures - Do not distribute
SMOV Flatfield
stretch +/-20%
Ratio of SMOV/TV3
stretch +/-3%
Additional Comments
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CALWF3 segv solution
– errors due to missing reference files