Re: [APML] NGC7000

[Stuart Heggie <stuart.j.heggie@sympatico.ca>]

Steve, I like the pic despite the rotation. Kind of grainy due to the 
push processing?

My sky fog limit at f4.5 is 45 to 50 minutes on ASA400. So, 60 minutes 
then pushed two stops is pretty wild. Probably better to take two 45 
minute pics and stack them. As for field rotation, what are your tripod 
legs sitting on? The G-11 with all that equipment is pretty heavy and it 
wouldn't have to sink much at all to spoil polar alignment which as you 
say is certainly the cause of the rotation. Was your guide star in the 
FOV? Experts say you should pick a guide star as close to the centre of 
the target as possible.

Given the colour of the NA nebula, many people are using E200 which is 
strong in red and responds well to push processing (they say). Might be 
an alternative.

The ST-8 and TV85 are a killer guiding combo - most folks would be 
imaging with that rig! They wouldn't bag the NA nebula though <g>.

All this from a beginner! Hope some of it is of use.

Stuart

Steve Lindsey wrote:

>I processed this one to see what 60 min at f4.5 with the 2 push Provia 400F
>did knowing that it had bad field rotation problem.  Turned out better than
>I expected in terms of what the film picked up after AV, levels and curves.
>
>I'd like your comments on what would be best for this same lens, film and
>processing the next time I try it to fix the field rotation.
>
>http://home.earthlink.net/%7estevelindsey/NGC7000.html
>
>Steve Lindsey
>
>
>
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