Lets say I might think how to set a minium diagonal.
If one draw a line from primary ( clear app ) to focal lenghts and one determate a L-distance.
Ok lets say it shows 7.5".
But if one draw lines and field stop in light cone included it means 8.25".
But from what I might realise now on diagonal's there are bevels on them to and one can't really use more than 90% out of them.
So even if I go on a 8" I will not be using or rely on more than 7.25", so I'm not get a 7.5" - as what I need even if I go 8".
Ok, so what is test show on used aperture on diagonals on high-end companys ?
I'm into a a waffle design as stiffer/lighter.
Thoose are in stock at even inches but of course one can do a special order or demand a clear app one need.
But I like to has test on them.
Before I thought using a lip at 1-2 mm radius - one would be ok.
Going on a to big diagonal means over 32%, and is that ok for a fast ex 25" visual Newton doing deep-sky.
Edited by hakann, 20 March 2017 - 06:52 PM.