public class CometProcessor
Semi-interactive batch processor which asks the user to point to a detected
"star" (typically a comet or minor planet) in each frame to be processed.
The frames are shifted to put that object at a constant position and then
accumulated (32 bits per channel). This is like the astro-combine process
using the method shift-brightest except that a comet is not likely to be
the brightest object in each frame and so the user has to help.