This page contains links to various WFPC2 and general Point Spread Function (PSF) pages, as well as Hubble Space Telescope focus information.
STScI PSF Documents:
- WFPC2 Instrument Handbook PSF Chapter.
- WFPC2 PSF Frequently Asked Questions.
- WFPC2 Photometry from Subtraction of Observed PSFs (PostScript, 1.6 MBytes) - Surdej, Baggett, Remy, and Wiggs, Oct. 1997.
- The WFPC2 PSF Library (PostScript, 0.29 MBytes) - Wiggs, Baggett, Surdej, and Tullos, Sep. 1997.
- WFPC2 Photometry from Subtraction of TinyTim PSFs (PostScript, 0.61 MBytes) - Remy, Surdej, Baggett, and Wiggs, Sep. 1997.
- WFPC2 Ghosts, Scatter, and PSF Field Dependence (PostScript, 5.5MBytes) - Krist, Aug. 1995.
Sources of Observed and Theoretical PSFs for WFPC2:
- WFPC2 PSF Library.
- TinyTim Home Page. Latest software version now includes field-dependent WFPC2 aberrations and the F1042M halo.
- John Bahcall's PSF Page.
Halo in WFPC2 F1042M Images: The GIF image below shows the observed F1042M image on the left, a Tiny Tim model without the halo in the middle, and the observed-Tiny Tim subtraction on the right. The Tiny Tim software now includes the halo. Each image is 9.8" on a side and displayed with the same log stretch.

Image courtesy J. Krist.
General PSF Information:
PSFs and Proposal Preparation:
HST Focus Information:
- WFPC2 Focus Report (PDF) - Casertano, Jan. 1995.
- Impact of Focus Drift on Aperture Photometry, Suchkov and Casertano, Jan. 1997.
- The Observatory Support Group's focus page.