Re: [APML] IC1396 in Ha /Tech Pan

["Jim Janusz" <jjanusz@dc.rr.com>]

Hi John,

Interesting, at 2 to 3 hours don't you think reciprocity will set in?  I've
never shot TP past 90 minutes.  Maybe Scott should stack two or three shots
rather than go that long?

Jim
----- Original Message ----- 
From: "John C. Mirtle" <spampit@shaw.ca>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Wednesday, September 24, 2003 2:10 PM
Subject: Re: [APML] IC1396 in Ha /Tech Pan


> Scott,
>     Looking pretty good for your second tech pan image! It looks like your
> lens has a "hot spot", probably exaggerated by the light pollution you are
> shooting through. The bright patch just to the right of 1396 shouldn't be
> there. You might have to do some Photoshop jiggery pokery on your images
> from town to reduce this. For comparison, have a peek at
> http://members.shaw.ca/astrophoto/files/ic1396bw.jpg done with a 180mm
f2.8,
> H-alpha and 60 minutes. It was shot from a mountain top 10 hours west of
> here back in 1991, it does not have the brightening your image does.
>     Exposure time varies so much, depending on sky brightness, how
effective
> the hyper is, development time, etc. I haven't shot through a
> telephoto/H-alpha combo for a while, but have been meaning to. I would
> probably start at 2 hours @f2.8, possibly 3. With my Schmidt @ f1.5 and a
> W92, I usually go for 45 minutes. But this is under good skies, as long as
> the aurora isn't active. If your scanner can't pull out an image, then you
> have probably gone too long. :-) It's hard to tell from this end if you
can
> shoot longer. The background density caused by light pollution will be
your
> limit. If the background is pretty thin, then shoot longer. If you have to
> hold it up to a mag -26 light source to see anything, then back it off a
> bit.
>
> John Mirtle
> Calgary, Ab. Canada
> http://members.shaw.ca/jmirtle
>
> ----- Original Message ----- 
> From: "Scott Hammonds" <shammonds@creatorsview.com>
> To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
> Sent: Wednesday, September 24, 2003 2:20 PM
> Subject: [APML] IC1396 in Ha /Tech Pan
>
>
> Hi List,
> This is my second reasonably successful Tech Pan image. I am still
> experimenting with processing these black and white images and I would
> appreciate comments and criticisms.
> I managed to get 2 shots last night before I needed sleep after
> returning from the Braves game, I'll try and post the other one later.
> http://www.creatorsview.com/pages/techpan.html
>
> Based on what you see from my images, do you think I should expose
> longer than the 50 minutes I have been using so far? Those of you
> shooting tech pan please let me know what you are using for exposure
> lengths.
>
> Thanks,
>
>
>
> Scott Hammonds
>
>
>
> _______________________________________________
> Astro-Photo mailing list
> Astro-Photo@seds.org
> http://seds.org/mailman/listinfo/astro-photo
>
> _______________________________________________
> Astro-Photo mailing list
> Astro-Photo@seds.org
> http://seds.org/mailman/listinfo/astro-photo


_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo