WFC3 SMOV Science Report
16/07/2009
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.
Proposal 11442, FGS-UVIS Alignment
•
Activity - Visit 1 of 1: images of astrometric cluster NGC188 in F410M
at 3 pointings using astrometric guide stars executed successfully
•
Objective – Map UVIS detector coordinate frame to FGS frame for SIAF
update
•
Status – Centroids of 5 stars measured for each pointing; astrometric
RA, Dec of stars and guide stars provided to Flight Ops Sensors group
at GSFC; V2,V3 values of stars returned to TEL group; V2,V3 of
reference pixel and orientation of detector in V2,V3 determined
•
Results
» UVIS apertures shift by (-0.6, 2.7) arcsec in (V2,V3)
» Rotation of ~0.07 degrees clockwise
» Measured scale ratio of 1.00025 (to be treated as 1.0 pending full distortion
solution)
» Incorporation of shift and rotation into WFC3 SIAF in progress
2
Proposal 11443, FGS-IR Alignment
•
Activity - Visit 1 of 1: images of astrometric cluster NGC188 in F128N
at 3 pointings using astrometric guide stars executed successfully
•
Objective – Map IR detector coordinate frame to FGS frame for SIAF
update
•
Status – Centroids of 3-4 stars measured for each pointing; astrometric
RA, Dec of stars and guide stars provided to Flight Ops Sensors group
at GSFC; V2,V3 values of stars returned to TEL group; V2,V3 of
reference pixel and orientation of detector in V2,V3 determined
•
Results
» IR apertures shift by (-1.0, 6.2) arcsec in (V2,V3)
» Rotation of ~0.15 degrees clockwise
» Measured scale ratio of 0.9989 (to be treated as 1.0 pending full distortion
solution)
» Incorporation of shift and rotation into WFC3 SIAF in progress
3
Proposal 11452, UVIS Flat Field
Uniformity
•
•
•
•
•
Visit 02 data in hand
– Acquired 31 exposures of Omega Cen in the filters F225W,
F275W, F336W (350 sec), F438W, F606W, F814W (35 sec)
Visit 01 will be made in the next 24 hours.
– Acquire 30 exposures of 47 Tuc in the filters F438W, F606W,
F814W (350 sec)
Objective – determine the difference between ground based CASTLE
flats and real flat fields
Status - analysis begun
Results – Analysis underway on F225W and F815W images
PRELIMINARY RESULTS
• Analysis of UVIS darks shows some correlation with
position of HST relative to bright earth.
• Dark current is up to ~5x larger than TV3 values
– 5 E-4 vs. 1 E-4 (ground) e-/second
– CEI spec is 5.6E-3 so we have lots of margin
Possible effect due to light leaking in around vent tube or via other
path.
Analysis is on going.
5
PRELIMINARY Results
Possible UVIS Light Leak
Y from Borders & S. Baggett
Embargoed figure - Do not distribute
X from McCullough & Jack MacConnell
6
UVIS Light Leak?
Embargoed figure - Do not distribute
*( Dark(ext4) = Dark(ext1) +-1E-4 )
7