Re: [APML] Converting CCD Workflow to Film?

["Jeff Crilly" <jlcapml@sbcglobal.net>]

Back in May with NEAT, I simply used the comet as the guidestar.

Here's a NEAT with the behive...
http://fototime.com/4183FB8C9ACD7ED/orig.jpg

The combo for this was: G11 (not gemeni), FSQ106, 200mm FL guidescope (camera lens),
ST7E using the big chip for guiding, CCDOps for guide software.

35mm Provia 400 was ued.  (this was before the pentax67 was aquired.)

It seemed to work, but maybe wasnt ideal. The CCD guys got way better results.

Clearly, with M45 this is tougher if you want to get M45 nebulosity intact.
I dunno how one would do that without compositing.

I now have a AP900 (as of about 1 month ago) and the "comet guiding"
feature is news to me.. I'll have to figure that out!

----- Original Message ----- 
From: "Thomas W. Earle" <twade@bmi.net>
To: <astro-photo@seds.org>
Sent: Monday, January 10, 2005 9:31 PM
Subject: [APML] Converting CCD Workflow to Film?


> As everyone is well aware of, we users film are at a big
> disadvantage with longer focal length telescopes/lenses while trying
> to capture comets along with their field of deep sky objects.  I'm
> trying to determine if it would be worth trying some CCD techniques
> in order to capture the deep sky objects in the field of view, along
> with the detail in the comet tail (i.e. you must guide on the
> comet).  The need for guiding on the comet is where the problem
> lies.  For example, if by some miracle the sky clears tomorrow
> (5/11), I'm going to try and capture it with my Pentax 67 300 mm
> F/4.0 and my Takahashi FSQ-106N.  Unfortunately, with the comet
> moving at 5.0"/minute, I'm only allowed 3 minutes 30 seconds and
> around 2 minutes, respectively, before the stars start to elongate.
> Even with fast film (i.e. NPZ 800 or Provia 400F pushed 1 stop),
> there is no way to capture the deep sky object too, much less the
> fainter tail of the comet.  In the following link, the author
> describes how he takes several shorter exposures, maintaining
> pinpoint stars, and combines them later:
> 
> http://www.ewellobservatory.com/ccd/comet.cfm
> 
> Would this even remotely work for film?  I understand that film is
> not linear; however, could this technique still produce acceptable
> results (i.e. adding frames to bring out the fainter deep sky
> objects and tail).  Any thoughts would be greatly appreciated.
> 
> Wade
> 
> 
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