Quote:
Originally Posted by AlexN
Rac: is it more or less difficult figuring a fast parabolic of smaller sizes? I'd love an 8" f/3.8 or f/3.3 however from what I know the smaller the surface the harder it is to figure faster and faster optics.
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I wouldn't know, I've only ever made two mirror and both are not small. It shouldn't be too much of a problem. It comes a point I think where you will need a sub diameter lap to get the correction into the glass, I'm not sure what that point is with an 8". I know with my 18" f3.3 I was having a hard time with an 8" lap so I did it with a 4" lap and it worked great but yet I could use the 8" lap all the way on my 20" f3.8, may have been how I was doing it though.
You learn so much every time and trying is the only way no matter how much you read on the net.