[ATM] baseline roc on a mirror with lost data..

[Dan]

Hey Yall,

Its been a long time since I posted for various reasons but now I find myself in a terrible place.

I took a loooong time off on the 12” f/5 I am making, and in that time my computer went belly up with all the spreadsheets and data with it. (lectures about backing up your data aside..........)

so, my question is how do I find a Zero point Roc in order to process my Couder results given that the average r for the center zone is not zero?...that is to say..how do I come up with a Zero from an Roc that I cannot measure as a sphere since I have already started parabolizing, and no longer have a sphere, with the additional caveat that all my original data is lost? (and that I still want to achieve the desired goal...a 12” f/5)...I can’t exactly say that what I ground and polished is EXACTLY what I was shooting for...it could be anywhere from an f/4.9 to a f/5.1 and those are silly numbers (and for that matter I couldn’t care less...I’m going for mighty close..not exact..I’m aiming only for Rayeidh Standard)...they could be BIGGER!!!!!! deviations...uhg.

anyone?..please help!

Your faithful enthusiast, and biggest dullard lurker that tries!

Norm