Re: [ATM] 8" f/3.5 !

[Steve Beccue <lsteve@beccue.com>]

Francis,

It sounds like it would make a really nice lensless schmidt as is.

Please see:
http://home.freeuk.com/m.gavin/schmidt_lens.htm


Steve Beccue
steve@beccue.com

On Sun, 14 Jan 2007, Francis J. O'Reilly wrote:

> 
> Many years ago, probably the mid to late 90's, I ordered a full thickness
> 8" pyrex pre generated blank from Newport glass. I wanted to build an 8"
> f/6 reflector. Unfortunately, I was very tired at the time and asked for a
> radius of curvature of 48 inches instead of 96 inches. I ground the blank
> out anyway and polished it. The radius of curvature is now 57 inches, focal
> length is roughly 28.5 inches. 
> 
> I put the glass under the knife tonight, a skill that I never really
> mastered, however, I try hard at it, and I determined that the mirror is
> most likely spherical, good for a point source, but definately not for
> light rays coming from many light years away so as to be nearly parallel
> when they strike my mirror. (Isn't space curved anyway Prof. Einstein?)
> 
> Any thoughts on the usefulness of this mirror, or am I wasting my time with
> something that will never give me much utility?
> 
> Best regards to all.
> 
> Francis J. O'Reilly 
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 
_______________________________________________
ATM mailing list http://www.atmlist.net/