Assigned ID: 652 ----- Attempting Submission 1 (Fri Feb 26 21:43:07 GMT 2010) ----- HST Phase I Proposal 652 (cycle_18_ar.apt) successfully submitted. ----- Attempting Submission 2 (Sat Feb 27 00:46:40 GMT 2010) ----- Astronomers' endless efforts to push to the limits of their scientific observations with HST ever increase the demand for the better knowledge of the instrument's PSF. We propose to carry out principal component analysis (PCA) of point spread function (PSF) for WFC3 and ACS/WFC. Both the cuspiness and the extended diffraction wing of HST PSF do not allow us to model it accurately using Gauss-Laguerre or Gauss-Hermite functions, which are commony referred to as shapelets. PCA by definition provides the optimal set of basis functions, which enables us to describe the position- and time-dependent variation of HST instruments accurately with as little as 20 basis functions or eigenPSFs. This study will construct a high-fidelity PSF model and provide the community with the library. This PSF will be described in the native pixel coordinate system of the detector prior to distortion correction. Therefore, the delivered PSF is of practical use regardless of the choice in drizzling parameters such as interpolation kernel, output pixel size, drop size, etc.

COSMOLOGY 12 81800 true 0.0 0.0 false false false false false false SUPPORTED