HDF Scattered Light Subtraction: version 2

In version 2 of the data reduction, we include frames where there is some visible scattered light, but where the background is still reasonably low (not more than a few times the minimum background). Scattered light subtraction is done as part of the final image combination, so that we can make use of the images at different dither positions to subtract sources from the images that are affected by scattered light.

Briefly, the scattered light subtraction was done by registering the bright and dark images, subtracting the dark from the bright to remove the source, smoothing to remove any residual sources left over after the subtraction, and subtracting this smoothed sky image from the bright frame.

Now for the details, for those familiar with the drizzling algorithm. For each band the steps are as follows:

Copyright © 1997 The Association of Universities for Research in Astronomy, Inc. All Rights Reserved.
Harry Ferguson ferguson@stsci.edu 3/1/96