[AZ-Observing] Re: Rigorous Precession

  • From: "Ken Sikes" <kengsikes@xxxxxxx>
  • To: <az-observing@xxxxxxxxxxxxx>
  • Date: Sat, 22 May 2010 11:02:39 -0700

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.


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