It has come to our knowledge that the 256 x 256 InSb array in
CGS4 suffers from small scale latent images. This problem has only
become noticeable since long integrations have become possible due to the
small pixel sizes in use with the long focal length camera.
In general, the latency only affects long exposures of very faint sources
after previously observing a bright source (e.g., a standard star). The
level of latency varies, but is usually less than about 5 counts (30 electrons)
above the general background level.
The simplest method to rid the array of the latent image is to ask
your TSS to run manpeak to take a few short exposures without changing
the apperture, once you are pointing at your faint source.
If your targets are bright enough to peakup on, then the above procedure
is unnecessary. The process of peaking up will remove any latent image.