Preliminary WFC3 UVIS PSF Evaluation

Details Preliminary WFC3 UVIS PSF Evaluation Preliminary WFC3 UVIS PSF Evaluation

Mar 2004

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004wfc..rept....8h&link_type=abstract

Instrument Science Report WFC3 2004-08, 10 pages

Statistics

Computation

Hubble Space Telescope, Hst, Space Telescope Science Institute, Wide Field Camera 3, Wfc3, Uvis, Psf Evaluation

Scientific paper

The flight UVIS CCD detector was aligned at Ball Aerospace to its mounting ring, based on previous measurements of the UVIS pathfinder detector at GSFC, and installed in the WFC3 instrument in November 2003. Alignment check measurements, made with the CASTLE telescope simulator, showed residual misalignment of the detector in excess of expected tolerances. Subsequent analyses showed that an error had been made at Ball during computation of the required alignment offsets, and two independent calculations verified the amended Ball methodology. With the source of the alignment error identified and the immediate impact on the program deemed minor, the flight detector remained in non-optimal alignment for a series of verification and preliminary calibration measurements, obtained in the SSDIF at GSFC in ambient environment in Dec 2003 and Jan 2004. We discuss the measurements of the UVIS PSF at four field positions, through four filters spanning the spectral range. The residual detector misalignment, after focus compensation with the onboard corrector and adjustment for image location offsets, has minimal effect on the PSF quality at the chosen field points near the centers of each of the quadrants of the FOV. The detector tip/tilt offsets will more noticeably affect the image quality at the FOV corners and render the camera more susceptible to focus drift effects (such as HST OTA "breathing" ), if left uncorrected. The measurements were made with the CASTLE "J" alignment, which represents its best-known match to that of the OTA with respect to the WFC3 latches. The UVIS corrector was adjusted slightly in tip/tilt, as well as in focus, to optimize the image quality near field center; the resultant corrector mechanism settings are shown in Table 1. Note that this may not be the ultimate best alignment of the corrector, since optimal balance over the field will likely require slight detuning at field center. The measurements presented here represent a subset of those planned for final verification of the instrument, in its flight condition and in a flight-like environment. That plan includes PSF evaluation at 16 uniformly distributed field points.

Affiliated with

Also associated with

No associations

Rating

Preliminary WFC3 UVIS PSF Evaluation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Preliminary WFC3 UVIS PSF Evaluation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Preliminary WFC3 UVIS PSF Evaluation will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1030608