Re: Re: [APML] life of a CCD (and Filters)

["Robert Gendler" <robgendler@worldnet.att.net>]

I have had a couple of custom scientific filters go bad
on me because of moisture getting within the layers of the filter.
Sometimes its very hard to see without shining a light directly
through the filter.
Rob Gendler
Email: robgendler@att.net
Web site: http://www.robgendlerastropics.com/
----- Original Message -----
From: "lkt" <tan@cox.net>
To: <astro-photo@seds.org>
Sent: Sunday, August 04, 2002 10:54 AM
Subject: Re: Re: [APML] life of a CCD (and Filters)


> Chuck,
>
>  Unfortunately, I did not get into much details on why he believed that
moisture was bad for the filters. I should have pursued this further but I
think I just took his word for it. Yes, he could have been
ultra-conservative about it. I recall after this discussion, he sold me many
packs of silica gel.
>
>  He is a very helpful person and spent quite a bit of time with me
discussing RGB and h-alpha filters. Someone might want to ask him to explain
the moisture issue.
>
> Loke
>
>
>
> >
> > From: Chuck Vaughn <aa6g@aa6g.org>
> > Date: 2002/08/04 Sun AM 10:35:22 EDT
> > To: <astro-photo@seds.org>
> > Subject: Re: [APML] life of a CCD (and Filters)
> >
> > Loke,
> >
> > What sort of data does he have to back this up? Has he run tests?
> > Does he have graphs showing degradation due to time and moisture?
> >
> > The only such test that I'm aware of is the one I ran. The filter
> > I tested was ten years old and appeared to have suffered no
> > degradation in that time.
> >
> > Certainly leaving a filter outside for 25 days exposed to the elements
> > including 14 days of rain and cleaning it every day should qualify
> > as accelerated exposure to moisture. :-)
> >
> > I've found that the filter manufacturers are VERY conservative about
> > how to handle their filters. This is fine since it's always a good
> > idea to be ultra careful with your optics.
> >
> > Step back and look at the big picture. Amateurs have been using
> > interference filters for at least 15 years now under all sorts of
> > conditions. If degradation was a common problem then we should be
> > hearing of this on a regular basis by this time. Yet reports seem
> > to be isolated and infrequent.
> >
> > Chuck <aa6g@aa6g.org>
> >
> > --------------------------------------
> >
> > > I spoke with David Marcus of Custom Scientific about this and he told
me
> > > that the coatings on their RGB filters do degrade with time and
> > > moisture. He advised me to keep them in a dry environment with Silica
> > > Gel.
> > >
> > > Loke
> >
> >
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> >
>
>
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