Stack a large number of images using multiple runs of the clip_stacker.sh routine (which can only stack a maximum of nine images at a time).

% big_stack --help 

Usage: big_stack list.all 7 mean AA 
arg1 - Name of file with list of FITS images
arg2 - number of images in sub-stacks 
arg3 - combine method (mean,median) 
arg4 - name string for combine level