Ok, I need some of you really smart people to help me. I'm running into design issues here. Here are the facts: 10" f/4.8 dob which will be used for visual observing only. I enjoy observing DSO's more than planets, but still like looking at the planets. FeatherTouch focuser, using 2" Naglers and new Pentax XW's. Also probably a Denk II binoviewer.
I've run all sorts of scenario's using the different size secondary mirrors and I think I need to go with a 2.6" secondary. When I ran the dimensions through NEWT it said there was "vignetting at focuser of 75% ray". Everything else was ok. Is this a big problem, or is it no big deal? I increased the focuser diameter by just .05" and the vignetting went away. So obviously it's just barely off.
I don't really understand this 75% and 100% zone ray concept. Can somebody explain it to me? It seems like all that should matter is the "On-Center" rays.
Do you think a 26% obstruction is really going to hurt my contrast? I could go with a 2.14" secondary(21% CO) but the FIF would be below .5". This wouldn't be a good idea, right?
I've run all sorts of scenario's using the different size secondary mirrors and I think I need to go with a 2.6" secondary. When I ran the dimensions through NEWT it said there was "vignetting at focuser of 75% ray". Everything else was ok. Is this a big problem, or is it no big deal? I increased the focuser diameter by just .05" and the vignetting went away. So obviously it's just barely off.
I don't really understand this 75% and 100% zone ray concept. Can somebody explain it to me? It seems like all that should matter is the "On-Center" rays.
Do you think a 26% obstruction is really going to hurt my contrast? I could go with a 2.14" secondary(21% CO) but the FIF would be below .5". This wouldn't be a good idea, right?
