Next: Richardson-Lucy Co-Addition
Sub-Stepping as a WFPC Observing Strategy
W. Freudling
Space Telescope - European Coordinating Facility,
Karl-Schwarzschild-Strasse 2,
D-85748 Garching bei München,
Germany
Abstract:
WFPC images offer a wide field of view but significantly undersample the PSF.
A strategy to recover some of the resolution lost by undersampling is to split
the exposure time into several images, which are shifted by a fraction of the
pixel size. These images can subsequently be combined with a modified
Richard-Lucy algorithm. One of the challenges of this approach is the treatment
of cosmic ray hits. A procedure to simultaneously co-add images with different
PSFs in the presence of CR hits is presented here. An IRAF implementation
(Freudling, 1993) was tested on both simulations and real WFPC data. These
tests show the viability of the proposed strategy.
Keywords:
WFPC, co-addition, cosmic rays