Re: [APML] Tri-Color Filters....Again!

["Jim Ives" <flyboy9990@earthlink.net>]

Thanks Chuck!
    Your testimony gives me a good vote of confidence that I won't get frost
bite for nothing!!
Jim
----- Original Message -----
From: "Chuck Vaughn" <aa6g@aa6g.org>
To: <astro-photo@seds.org>
Sent: Wednesday, December 18, 2002 10:30 AM
Subject: Re: [APML] Tri-Color Filters....Again!


> Jim,
>
>
> > Hi Roland thanks for answering. I think it is dielectric. I held up
> > the blue filter to a light and it changed to purple as I tipped it. I
> > couldn't see the change though till I was holding it at a pretty steep
> > angle though. We'll see how it goes. I will post the results to the
> > list.
> > Jim Ives
>
> I doubt you'll have a problem with RGB dielectric filters. I looked
> into this issue years ago when we had our 15nm H-a filters made. I have
> a friend who uses one with an E-160 and it doesn't shift too much. RGB
> filters are so broad and should have gentle enough slopes that a shift
> of a few nanometers will not be a problem.
>
> The time you need to worry about a narrow filter is when a shift of few
> nanometers will move an emission line out of the peak of the bandpass.
>
> Chuck <aa6g@aa6g.org>
>
>
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