I seem to have noticed that (i)mosflm can index on one image, or two images that are not related by 90 degrees. also, cell refinement sometimes splits up a set of frames into maybe 3 or four segments of e.g. a few degrees each. and of course, I can set it based on frames 90 degrees apart. reason I ask is that i thought mosflm's modus operandi was based on frames in general being related by 90 degrees - is mosflm simply written differently or is there some criteria it uses to make these settings, or something else... -Bryan