From: RayRochelle (r.rochelle_at_antispamdomain.not)
Date: Mon Dec 01 2003 - 00:19:31 EST
Bill,
This is a post from APML on our subject HTH
Ray
----- Original Message -----
From: "John C. Mirtle" <spampit_.at._shaw.ca>
To: "Discussion of Film Astrophotography" <astro-photo_.at._seds.org>
Sent: Sunday, November 30, 2003 2:02 PM
Subject: Re: [APML] Sky Pollution Astrophotography - on film
> Nicely done Bill!
> It really is amazing how well the Lumicon H-alpha or W92 cut through the
> crud with either tech pan or E200. I used to shoot from in town as well,
> back in the mid 80's under mag 4 skies. Back then I used to focus with a
> Deep SkyŽ filter and then swap in the H-alpha. That is how I got my first
> shot of the cone nebula! At f4.5 I found the exposure times reasonable even
> using tech pan. These filters also work well with moonlight, as you can see
> with http://members.shaw.ca/jmirtle/gammacyg.htm . The last quarter moon was
> up for that shot. If you want to shoot larger planetaries, a UHC filter
> works well too.
> You are showing a bit of vignetting. If you could reduce that, you
> should be able to tease out a bit more "stuff" from the image. Nice to see
> some tech pan images!
>
> John Mirtle
> Calgary, Ab. Canada
>
> ----- Original Message -----
> From: "William R. Mattil" <wrmattil_.at._ix.netcom.com>
> To: <astro-photo_.at._seds.org>
> Sent: Sunday, November 30, 2003 3:24 PM
> Subject: [APML] Sky Pollution Astrophotography - on film
>
>
> > Gentlemen,
> >
> > I spent a bit of time cobbling together using surplus 48mm filter
> > casings and some wratten filters (#92 and #2B) a deep sky nebula filter.
> > The idea was to use the #2B to focus through and then replace it with
> > the #92. I mean this works for Schmidt Cameras so it should work at F/4
> > right ? This resultant filter attaches to the Lumicon "T" ring after the
> > OAG prism So the ST-4 doesn't have to deal with it :^). I thought that
> > this would be useful for doing testing from my extremely light polluted
> > backyard and ironing out system problems so that trips to a dark sky
> > aren't wasted. To be honest though I was a bit surprised at the results,
> > after ironing out a proceedural issue with the knife edge focuser
> > (Thanks Jerry !) The results are far better than I ever hoped for.
> >
> >
> > http://www.celestial-images.com/B33.html
> >
> >
> > This is a full frame scan. No cropping and very slight curve adjustment.
> > Specifics are as follows:
> >
> > 45 minute exposure on hypered Tech Pan using a 253mm f/4 with Lumicon
> > OAG and coma corrector. Guided with the ubiquitious ST-4. Some
> > vignetting is apparent and its not too difficult to see where the shadow
> > of the pick-off prism is :^) I probably should modify the Nikon F with
> > some tape to take up some of the extra slop when using Tech Pan and a
> > dry air purge wouldn't hurt either but comments would be most welcome
> > including any Photoshop processing tips.
> >
> > I shot a total of three of these, 45 min, 30 min and 20 min. And may try
> > stacking them.
> >
> > Regards
> >
> > Bill
> >
> > --
> > William R. Mattil |
> > wrmattil_.at._ix.netcom.com | http://celestial-images.com
> > (972) 399-4106 |
>
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