Re: [APML] H-alpha solar photography nightmare

["Bert Katzung" <katzung1@attbi.com>]

Hi again, Emmanuele:
I responded to your post to Chris before seeing this post, so this may be
repetitive---sounds like Lumicon was trying for something very competitive
with the Daystar system. Maybe lacking only the heater for maintaining the
pass band constant. I think the posts on the CCD lists were by ? Ward and by
Ron Wodaski. Seems that by manipulating the image heavily, masking the sun's
disk, etc, they were able to bring out prominences pretty well in CCD
images. They didn't attempt to see anything visually.

Well, the Lumicon system  sounds interesting and if it works out, let us
know.... It would be interesting to try it out with a digicam or CCD
camera., since you can see the result immediately.
Bert

Bert Katzung
katzung1@attbi.com
www.astronomy-images.com

----- Original Message -----
From: "vega" <vega@ulisse.it>
To: <astro-photo@seds.org>
Sent: Monday, October 07, 2002 12:16 AM
Subject: RE: [APML] H-alpha solar photography nightmare


> >===== Original Message From "Bert Katzung" <katzung1@attbi.com> =====
> >Hi Emmanuele:
> >I think the Lumicon H-alpha has a pretty broad bandwidth (around 10 nM or
> >greater?) for sun work unless it's a special filter that I don't know
about.
> >The Lumicon H-alpha filter that I have is a standard non-solar filter for
> >imaging H-alpha nebulas and it has a pretty wide bandpass. As you know,
the
> >DayStar and Coronado solar filters work down around 0.3 to 0.8 nM
bandwidth.
> >I believe the non-solar H-alpha filters that have been mentioned recently
on
> >the CCD lists for solar prominence imaging were Custom Scientific's 3 or
4
> >nM bandwidth filters.
>
> Hi Bert,
> according to the filter's manual, the filter _is_ designed and intended
for
> visual use (see my post in response to Chris Cook), and I'm quite
surprised
> that nobody has never heard about it. It has a bandwidth of about 1.5
> angstrom, i.e. 0.15 nM. The Coronado filters and the like have bandwith
lying
> around 0.3 to 0.8 (as stated on their website), which means between .03
and
> .08 nM (1 nM = 10 angstrom).
>
> >I'm a little unclear on how you positioned your filter(s). If I
understood
> >the recent CCD posts correctly, you should use a regular solar filter
(eg,
> >Baader film) over the objective (just like solar visual observing). Is
that
> >what you mean by the "IR prefilter"? The H-alpha filter should go at the
> >camera end. Add neutral density filters of any type as needed to get the
> >exposure up to something you can achieve with the camera you're using. (I
> >haven't tried solar imaging with an H-alpha filter of any kind, so I'm
> >speculating here. I am interested in trying my CCD camera on it, though.)
>
> In fact, the Lumicon solar filter comes with a prefilter, mounted on a
> telescope cap, that absorbs 95% of the incoming infrared radiation: then,
the
> remainder has to pass through the actual filter, which is mounted _before_
any
> eyepiece or any astrophoto gear. The actual filter is cylinder about 1 cm
> (.4") high and 10 cm (4") in diameter, which is intended to fit onto 1.25"
> tubes. Then it also has a small knob, by means of which the user can
adjust
> the filter's tilt by +/- 3 degrees. This fine tuning should allow for
better
> viewing (shooting?) of fine chromosphere details.
>
> Does it make sense now?
>
> Emmanuele
>
>
> --  APML Archives at <http://astro.umsystem.edu/apml/>  ---
>              Unsubscribe at <majordomo@seds.org>
>



--  APML Archives at <http://astro.umsystem.edu/apml/>  ---
             Unsubscribe at <majordomo@seds.org>