Re: ATM Alt-alt telescope mount - and image rotation

[mdholm@telerama.com]

Tom,

I just (literally) did some hand waving and convinced myself that you would get 
less field rotation with first axis east-west rather than north-south. It 
probably depends on latitude.  Below 45 degrees this may be true.  Above 45 
degrees the north-south orientation would yield less rotation.  At the equator, 
a north-south, alt-alt is an equatorial.  At the poles, an alt-az is an 
equatorial.

No orientation other than equatorial gives no rotation.

Sorry, I don't have the equations for that transformation.

Mark Holm
mdholm@telerama.com