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Celestron 925SCT + f6.3 reducer + Lodestar


kerrylewis
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Hi Kerry,

The spacing between the FR and the camera sensor is important in obtaining the desired reduction. The spacing between the back of the SCT and the FR also affects the reduction, but is minor. That's because the mirror position changes which also affects the scope's FL. The spacing required depends on what FR you have. Here is a calculator that I use to get me close.

http://www.wilmslowastro.com/software/formulae.htm#FR

If you have an Antares like I do, the FL is 225mm and the spacing to get .63 is 84mm. Meade and Celestron will be different.

One thing to caution you on is the focal length you will be working at with that setup. It will be close to 1500mm. That's a very narrow field of view with the small sensor of the Lodestar. Last night I was using my Meade 8" SCT with the 6.3 reducer. Here are a couple of captures of popular objects. Your alignment and tracking will have to be spot on. I was at 1260mm FL, so your FOV will be even narrower.

Hope this helps.

Don

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