I have just purchased a 12-1/2" F3.9 newt/cass mirror. I plan on building a dob style scope for it but have a few questions. BTW, this will be a first time venture for me so if I've missed anything that might be critical speak up.
Diagonal size will probably be a 3" which will give a 100% illuminated spot close to 1". Will this be sufficient for most applications (1-1/4" and less expensive 2" eyepieces)? I got a 2-1/8" with the mirror but I think this will be way too small.
Paracor, I think this will be a must. Does it require any additional in or out focus?
Mirror cells, The only one I know about is University Optics and I've heard they are on the light side. Any others?
I'm thinking about a curved spider, good, bad?
I think that's it,
for now.
Thanks,
Robert