Re: [ATM] Re: Figuring the little dinky sphere

[aneves@snowsoft.biz]

David,

I guess that blocking various lenses together would be alot better, but blocking such a strongly curved lenses requires machining a hemisphere tool to attach the lenses. When I started making this reference element, I decided to make a lot of 10 to provide other ATMs with a reference so that more amateurs could have a spherical fizeau interferometer and not break their bank account. I got some zerodur and cut out the blanks, made the required brass tooling and rough ground all the surfaces of the 10 lenses. I decided to first try polishing one of them to get some experience and that is where I am at the moment. 

In regards to testing this lens I think the right way is to make a proof plate. I've been trying to skip this, but I think it is the only way I could garranty a 1/10 wavefront for the reference element. Pity that I do not have access to a Zygo to certify the reference elements.

Regards,

Alfredo

P.S. To all those that have not made a lens before, I would strongly recomend the experience of making your own lens.

club here in Chile.

----------------------------------------
 From: "David Harbour" <scarab2@cox.net>
Sent: Thursday, June 16, 2005 10:20 AM
To: "ATM List" <atm@atmlist.net>, <aneves@snowsoft.biz>
Subject: Re: [ATM] Re: Figuring the little dinky sphere 

Alfredo,

I think Richard's last reply, and my addendums, probably constitute the best
advice you can get. I think that a null test is a test that let's a guy off
very easily; I am wondering, though, if on optics that small, there might
not be polishing routines that will "automatically" yield the required
figure.

For instance, I remember the technique of mounting several blanks in a
matrix, and grinding and polishing them flat. This usually works very well;
you are not trying to treat a single small mirror, but essentially, a single
large mirror (whose pieces you later "break out" and have several finished
elements). Perhaps something like this might be the answer to you guys
trying to make these dink
ntal stone, or whatever, and grind a "big" sphere; then, "bust
'em out" after they're done. I don't know. Look at all the late posts.
Thanks for seeking my wisdom (which is pretty limited, I promise you)-

Dave

P.S.- I think you are on the right track, Alfredo. "Keep on 'a truckin'"-

----- Original Message ----- 
From: 
To: 
Sent: Wednesday, June 15, 2005 1:35 PM
Subject: [ATM] Re: Figuring the little dinky sphere

Hi David,

Please consider that I am trying to do the same as Richard but on a 1.25"
negative meniscus. So far I have been using the beam splitter and a ronchi
screen to figure my refrence element 2 sides!

Regards,

Alfredo

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