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getting a flat coated

Started by Phil Barker, 09/08/2002 08:04PM
Posted 09/08/2002 08:04PM Opening Post
Am about to embark on folded newtonian scope. I have the secondary and primary both extremely fine optics.

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.



Posted 09/09/2002 07:46AM #1
Phil,

Just a thought: how about getting your flat coated locally at the same time as the primary. Then when you get your design perfected, and if you feel you need a better coating on the flat, you could have it done then.

In the USA, Spectrum seems to be top dog among those who do amateur optics.

Brad