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That would be a brave estimate!
No - find the focus point of the Newt like this. Rack the focuser all the way in - I removed the 1.25" adaptor as I intend to use a 2" T adaptor on the camera.
Point the scope at the moon - take a piece of white card and hold at the focuser opening, move back and forth (along a tape measure held against the focuser) and you will see when a focused image is produced - this is where you want the CCD in the camera. In mine it was 36mm from the end of the focuser.
Since the CCD sits about 42mm back in the camera body (measured with carefully lowered toothpick to the side of the CCD), and the T-adaptor takes up 13mm or so, I worked out I needed *at least* 20mm or so extra in-focus.
Because a 35mm extension piece is readily available, I decided on taking 35mm off the tube, this way the camera should easily obtain prime focus, and the 35mm extension tube should allow all my EP's to work exactly as before.
You have a nice big moon tonight - should be easy to work out where the focal plane is relative to the end of the focuser.
I'm going to test the camera on the Newt tonight with the full moon, hope to post a report in this thread before too long.......
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