ACTIVITY TITLE: UVIS Image Quality
ID: WFC3-23 (11436)
APPLICABLE SMOV REQUIREMENTS: 1.2.2
DESCRIPTION: The UVIS imaging performance over field will be assessed in two passbands to verify PSF encircled energy CEI specifications at 250 and 633 nm, after the instrument has been aligned to the OTA. The observed field must be sufficiently dense to provide good sampling over the FOV while providing enough isolated stars to permit accurate PSF measurement. If the field is astrometric and astrometric guide stars are used, the plate scale and image orientation may also be determined. NGC-188 star 58 is a likely target, available year-round and used previously for ACS alignment. The F275W and F621M filters will be used. Full frame images will be obtained at each of 4 dither positions designed to improve PSF sampling. Sampling of the field may be improved by larger POS-TARG offsets.
IMPLEMENTATION METHOD: SMS
DEPENDENCIES: This must occur after the final visit of WFC3-21, UVIS Fine Alignment, and the resulting corrector settings have been applied
DURATION: 2 orbits
DATA REQUIREMENTS: 12 full frame UVIS images (~400 MB) will be generated.
ANALYSES & EXPECTED RESULTS: PSF analyses (encircled energy, sharpness, FWHM, PR) will be performed to assess imaging performance over the field.
COMMENTS: AUTHOR/telephone/email: George Hartigfirstname.lastname@example.org
DATE: 25 Jan 2008