[mura_gadi (Steve)]

Hello,

Sorry, diffraction spikes was what I meant, I liked the thought they reduce as you get slower in a newt. I seem to remember at F9 they should be nearly eliminated, a feature I thought would be nice visually for clusters/planets etc.

I'll make a 205/6mm or so lap with the concrete and PoP tomorrow. The cure time will be a good chance to get started on the other test aspects of this endeavour.



Thanks again for your help and input
Steve
Ps.
The whole F/L idea is based on 1800mm roughly as I am 6'1"+ and closer to 6'4" in the moon boots. I wanted a F/L on a Dob that after the base was added and the eyepiece at close to apex I wouldn't need more than 1 foot step to use the scope. (Box with a pole on one side sort of step/support)

The starter is 8" at F9, the final a F5 16" (F4.5 18" if I can get away with a 25mm thick mirror) and a 12" in between to help learn how to work a steeper bigger mirror prior to the 16"/18". I wanted to see if I like the 1800mm F/L prior to committing to the 16"/18".

The scope building starts with my tester stand, so, the 1800mm maybe scrapped sooner... I'm hoping to get a cheap 2nd hand 8" GSO to strip parts from to build the mirror tester on a plank sort of thing for the star testing.