Quote:
Originally Posted by Zed
I have some basic knowledge about optics, so the focal point of the primary must fall on the secondary within a couple of mm....
|
When you rethink that, you'll realise that that the focussed image actually has to fall close to the eyepiece. The eyepiece allows you to magnify that image or the bit of it you want to see.
(aside - leave an eyepiece out of the focusser and put a partly opaque cover over it and point the scope at the Moon. Adjust the focusser up and down and you should be able to see an image of the Moon focussed on that cover!)