RE: [APML] H-alpha solar photography nightmare

["Sky Optics" <sbarnes@skyoptics.net>]

Hello,

	Lumicon did make a solar H-alpha filter for observing
prominences only. It is safe and intented for solar viewing (if used
properly). 

Steve Barnes

-----Original Message-----
From: owner-astro-photo@seds.org [mailto:owner-astro-photo@seds.org] On
Behalf Of Emmanuele Sordini
Sent: October 6, 2002 5:33 PM
To: astro-photo@seds.org
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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