Newt Software

I have been using Newt to play with the parameters for a 16 inch truss tube scope. I have the rocker box, Mirror box, Mirror cell and the secondary cage all complete but now am looking at changing the F- ratio to make completion of this self figures mirror easier. I have a 16 inch blank and a 3 inch secondary diagonal mirror and originally I was looking at about F4.75 but now I think I want to go about F6. This changes the 100% illumination diameter and also causes vignetting of the 75% illumination at the enterance and the focuser. I can't really see this as any big deal. Currently the mirror blank is hogged to F6.5 but I have a long way to go to completion. What am I missing.

Thanks Dave

At f/6 the 3" secondary is way too large unless you go to a 3 or 4 inch focuser because of the larger light cone. Something like a 2.5 to 2.6 inch will probably be much better.
I am currently working on a 16" f/5.7 and will be using a 2.5" diagonal.

Walter