AJ, I am familiar with the program you are talking about, Bill Anderson and I once talked about the 1875 version. At that time the constellation boundaries followed simpler lines. Over time the boundary lines have changed and that program is not as accurate. There is a newer program, but it is difficult to use. When you say "objects" are you referring to DSO's or stars? If stars one has to take into account the proper motion of the star as well when calculating the new location and constellation. Bill and I had a very long and deep conversation about this one time at Hovatter and he concluded that the new program would be more work that gain. If one was going to precess coordinates to a specific date say Aug 20, 2010 then the primary constants would remain the same and the only change would be the spherical coordinates. The book I mentioned to Stan is excellent for this and you are welcome to borrow it if you like. Ken -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.