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

[lkt <tan@cox.net>]

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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