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

["Tom Krajci" <tkrajci@san.osd.mil>]

>From: 'mdholm@telerama.com'
 
>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.

Have you looked at:
http://www.covingtoninnovations.com/astro/Polar.html

You can plug in numbers for small misalignments...typical of an
equatorial scope with slight alignment error...or you can plug in really
large misalignments to model the image rotation behavior of an alt-az or
alt-alt design.

Do the results this applet provides match with your hand waving?

Tom Krajci
Tashkent, Uzbekistan
 

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