RE: [APML] Wratten 2E replacement

["Dale Ireland" <direland@drdale.com>]

R.R.
The Wratten 2E has a cutoff at 415nm.
You could use a B+W 415 (415nm cutoff)
or a B+W 420

The 1A is completely different.
Dale

>
> -----Original Message-----
> From: owner-astro-photo@seds.org [mailto:owner-astro-photo@seds.org]On
> Behalf Of Roland Roberts
> Sent: Thursday, December 26, 2002 9:51 PM
> To: astro-photo@seds.org
> Subject: [APML] Wratten 2E replacement
>
>
> I've often seen the recommendation of using something like a Wratten
> 2E to reduce blue halos around star images.  However, my normal
> dark-sky site eats gel filters---my site is in a river valley and I
> basically get one use out of the filters.
>
> So, is there a glass equivalent made by anyone?  Is a skylight 1A a
> reasonable choice for this or do I need something with a more
> agressive cutoff?
>
> roland

>



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