RE: [ATM] Large Secondary

["Peter" <peter@kitgear.com>]

Hi Mike,

The mirror is an ex-military flat purchased from Surplus Shed so I do not
know the material but it looks like Pyrex or BK7. The back is fine ground so
I cannot check for stress unless you know of a way to check the coated
front? The thickness is 0.800". I checked the mirror using a 5.5" reference
flat and a monochromatic source and the mirror surface looks good.

Ideally I'd like to have an elliptical shape 7" x 7.8" flat. If members of
this list feel that I can diamond cut the mirror then I'd select to cut
1.225" off each end.

Thanks,

Peter

-----Original Message-----
From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net]On Behalf
Of Mike Lockwood
Sent: Wednesday, June 29, 2005 4:50 PM
To: ATMList
Subject: Re: [ATM] Large Secondary


Peter,

Peter wrote:
> I have a bit of a dilema and I'd like to ask your advice.
>
> I'm making a large folded newt and I have aquired a low cost 7.25" minor
> axis diagonal (10.24" major axis) which when mounted at an 18 degree
folded
> angle in my scope will create too large and non-uniform obstruction.
>
> Can I cut one side of the diamonal on a professional diamond saw or will
> this action damage the overall optical figure. The mirror tests very well
as
> compared to a good reference flat but I fear destroying this optic.

What is the substrate material, and how thick is it?
Have you checked it for strain?
What is the final flat size that you require?

	Mike Lockwood



_______________________________________________
ATM mailing list http://www.atmlist.net/

_______________________________________________
ATM mailing list http://www.atmlist.net/