WFPC2 Instrument Science Report 94-01:
Large Angle Scattering in WFPC2 and Horizontal "Smearing" Correction
by John Krist and Chris Burrows
Abstract excerpted from the report:
The horizontal "smearing" seen in highly saturated images can be reasonably corrected using an exponential function which decays over a few rows after a saturated pixel is encountered. The effect itself temporarily saturates after about 10 saturated pixels (subsequent saturated pixels have no effect). The effect is about 2X worse in the 7e- gain channel than the 14e- gain channel. The correction only works on very highly saturated stellar images.
The large angle (>3") scattering in WFPC2 is significantly greater than that measured in WF/PC-1. At 20" from a star, it is an order of magnitude greater than WF/PC-1. The additional scatter is due to WFPC2, no the OTA, and includes high frequency structure which is position and wavelength dependent.
The Complete Paper is now available, (Post Script, 29.0 Mbytes).