Posted By Phil Barker
The flat is better than 1/10th wave the primary purchased thru astromart for $900 a 20 inch f-6.05 is 1/14th wave on the wavefront and zone free according to my foucault tester.
I still can't believe what a bargain that primary is. 2 inch fine annealed pyrex to boot!
I wish to get the flat enhanced coated or if possible the new 98% coatings we all hear about.
Is this possible?
Any help appreciated.
The design if your're interested has the primary 92.5 inches from the 6 inch secondary with a tertiary then diverting the light to the focuser which is low profile.
Full illumination over 1.2 inches results which will do nicely.
The primary can be coated locally for peanuts(about $75US) but only standard 89% coat available and I'm not paying to send it overseas.
I live south of Australia in New Zealand.