Yes, it's for the f4.5 project. I used Newt for the Web as the calculator and I only have a small window to make changes in or I introduce vignetting into the light path. Right now I'm at a inner tube diameter of 15.625, 20% obstruction, and I bumped up the illumination zone to...
A 9 year old chooses between a small Go-To refractor and a small Dob after using both - here's a post every person trying to choose a scope for a child, could potentially benefit from What can be expected when the telescope arrives - a member photo documents his experience assembling an...