To: atm{at}shore.net
From: MLThiebaux 
Reply-To: MLThiebaux 


Thanks to those who sent comments and references re my question on
overdetermined math in Go-to mountings [Fabio, 3 Jun 2003 09:18:19 -0700;
Greg, 03 Jun 2003 08:20:28 -0400].

I know of several approaches to the problem and I wanted to see what was
actually done in practice.  Personally I would have started with a perfect
mechanical system (perpendicular axes, rigid structure, no atmosphere,
etc.) and used the exact formulas from spherical trig as a foundation to
handle the bulk of the transformations.

Random and systematic errors could then be accounted for as polynomial
corrections to the exact formulas.  The extent of the corrections (number
of stars used in the initialization) could be chosen by the user depending
on the application.

The references seem to bypass the spherical trig foundation, but probably I
am mistaken.

Martial Thiebaux
Rawdon Hills, Nova Scotia

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