Re: [APML] TP development results

["westergren" <westergren@netzero.net>]

Jim,
I got Wratten 25 material (thin gel film) and made my own holder to screw
into the lens.  I got it from www.edmundoptics.com

I have also used a photographic filter made for cameras (look for R1(cut off
at 580 nm) or R2(cutoff at 600 nm).  These are available in any camera size
at well stocked photo stores. Online,  you can go to www.2filter.com for
prices on filters.  They are very knowledgable, but you have to call on the
phone to order.  They are glass and have some thickness, but I haven't seen
any significant change in focus using one.  The glass type is much more
durable and not subject to moisture like the Wratten gel filter.

Incidently, there's no way for me to focus through one of these filters
because even the bright stars are too dim for my eyes.  The stars show up in
the photos though. I just focus normally then put the filter in and take the
exposure.

Don
----- Original Message -----
From: "Jim Ives" <flyboy9990@earthlink.net>
To: <astro-photo@seds.org>
Sent: Friday, March 29, 2002 12:09 PM
Subject: Re: [APML] TP development results


> Hi Don,
>     Where exactly can you get a Wratten #25??
>




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