Re: [APML] H-alpha solar photography nightmare

["Brian Larmay" <astrobri@ameritech.net>]

I dont believe this is the intended H-a filter for solar observing.

If anyone cares to expound, im all ears too

Brian


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A little bit longer
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----- Original Message -----
From: "Emmanuele Sordini" <vega@ulisse.it>
To: <astro-photo@seds.org>
Sent: Sunday, October 06, 2002 4:33 PM
Subject: [APML] H-alpha solar photography nightmare


> Hi everybody,
> here comes a report of my troubles with a Lumicon H-alpha filter (which,
by
> the way, has nothing to do with Lumicon going down the tubes). Some days
> ago, I met with a friend of mine in an attempt to use his Lumicon filter
> for observation and photography of solar prominences and the like.
> We used a 102-mm Vixen achromat refractor, for which an adapter was made
to
> fit the IR prefilter on the objective lens, which is conceived for a 8"
> SCT. Here are my first use impressions:
>
> 1) The Sun looks like a very bright red fireball, too bright for anybody
to
> tell such elusive features as prominences. Probably the filter is made for
> photographic use, not visual.
> 2) Focusing is, as usual, a pain in the butt, even with my Nikon F3
> equipped with D red-dot focusing screen and DW-4 magnifier.
> 3) Needless to say, we didn't notice any prominence whatsoever, even
> adjusting the filter tilt. I saw breathtaking pictures of the solar
> chromosphere but I've actually seen no hint of anything through that
> filter. Perhaps should the bandpass be even narrower?
>
> So here come my questions:
>
> A) Are any structures supposedly visible with an H-alpha filter so
> difficult to find? I have a hunch we should have used a high magnification
> (i.e. 100x at least) and should have carefully scanned all the Sun border
> for something. Am I correct?
> B) Is focusing the same as deep-sky of regular solar photography?
> C) Are there any special tricks that I am not aware of, or is the filter
> out of order (which I strongly doubt)?
> D) What can be seen/shot through those filters?
> D) How does the Lumicon compare with other competing products (Daystar,
> Coronado,...) as to usability and performance?
>
> I apologize for my long post but I am in dire need of answers. Any help
> will be greatly appreciated.
> Thanks in advance and clear skies,
>
> Emmanuele Sordini
>
>
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