`ccube` is a cube computer. It accepts arithmetic expressions
mixing numbers and FITS files to perform basic arithmetic. Do not
search any further if you are looking for a command-line way to divide
an image by a constant (normalization), or divide all planes in a cube
by an image (flatfielding), or subtract an image from all planes of a
cube (sky-subtraction), or compute the average image from 3 planes,
etc.

Nicolas Devillard 2002-04-01