On Fri, 3 Nov 2000 13:50:32 -0700, <aah@nofs.navy.mil> wrote: > I think >both Michael and Andrew have shown that they can get ~0.5arcsec >accuracy over the entire frame. The last two images I processed were down to 0.1arcsec probable error in both RA and DEC with a cubic fit. That's using Tycho2 with proper motions. That is a non-problem! Andrew Bennett, Avondale Vineyard, Nova Scotia, Canada.