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Old 03-10-2007, 04:18 PM
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netwolf
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Mike, there is one other issue inherent with Alt/az Though you can use a Field derotator to avoid FR, inacuracy's in the mount will lead to the need for guiding. This is a bit more tricky as you have field rotation to content on the guidescope. Chuck Shaw has done some work on this and provided a working solution.
http://www.ghg.net/cshaw/guiderot.htm

An alternate method that I saw the math for that works theoretically is using a Alt/Alt/Az mount. Mel Bartel did the calculation on such a mount and found that it would not be affected by FR. However as yet i Dont think a drive system has been created for it.

But practically speaking I think you need to define what you want first. Because there are two many choices and some impractical and very expensive. I would suggest you establish a list of things you want to do.
1. Visual, DSO up to what magnitude.
2. Visual, Planets (image scale).
3. Imaging Planets
4. Imaging DSO Widefield.
5. Imaging faint DSO's , decide limiting magnitude.

And importantly, portability ease of setup and use is also a factor for Scope's that you want to travel with.

Be waned this may lead to more than one scope.

I have my LX90 and considered taking the OTA off it but I learned from my first trip to Kulnura that the power of the LX90 was as a portable visual scope that was quick and easy to setup. It has planet imaging potential, but image scale is limited by pointing accuracy and tracking accuracy. I can go up to F30 beyond that it gets very hard to archive. DSO is doable using a wedge, 5ash (i think he is the one) has done some great shots using this setup with a Canon DSLR.

But eventually by imaging platform will be built around the G-11 mount.



Regards
Fahim
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