[ATM] Interferometer Fringe Contrast From Coated Mirrors

[jlerch1 at tampabay.rr.com (James Lerch)]

----- Original Message ----- 
From: "Donald "Don" Ware" <mimas@charter.net>

>
> Roger at the Mirror Lab in Arizona suggested using a pellicle filter.  These
> are actually sold as pellicle beam splitters, transmitting a percentage of
> the ray and reflecting the rest.  The one I was able to find transmits 67%,
> which, because the ray passes through twice actually reduces the light from
> the mirror by about 60%.
>
> While a pellicle beam splitter that transmits 50% or even 40% would probably
> be better, I am getting quite good fringe contrast from coated mirrors.
> The fringes are only slightly broadened due to the extra optical elements in
> the path.

Excellent update Don!

Where did you get the pellicle filter?  How much was it?

Would this work?
http://www.surplusshed.com/pages/item/m2068.html

Take Care,
James Lerch
http://lerch.no-ip.com/atm (My telescope construction,testing, and coating site)

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