  The results of recognition of cosmic ray (CR) signatures on a single image
were analyzed for several codes written by several authors. For most visual
images made during low solar activity at exposure time t>4 s, the number of
clusters of bright pixels on an image per second per sq. cm of CCD was about
2-4, both for dark and normal sky images. At high solar activity, it sometimes
exceeded 10. The ratio of the number of CR signatures consisting of 'n' pixels
obtained at high solar activity to that at low solar activity was greater for
greater 'n'. The number of clusters detected as CR signatures on a single
infrared image is by at least a factor of several greater than the actual
number of CR signatures; the number of clusters based on analysis of two
successive dark frames is in agreement with an expected number of CR
signatures. Some glitches of false CR signatures include bright pixels
presented on different infrared images. Our interactive code allows one to
delete long CR signatures and prevents removal of false CR signatures near the
edge of a comet.

Astrophysics