Re: [APML] Help with M8 on Tech Pan

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

Thom, I'm no expert on Techpan but my observations for what they're worth:

    * if I tilt my laptop screen way back it seems to be an oddly shaped
      but kind of circular vignetted/light-fall-off pattern but it is
      not precisely circular nor is it in the centre of the fov.
    * unless you have processing artifacts, there are odd structures to
      the light and dark especially in the upper left and lower
      right.Not clear how this could be induced by mechanical vignetting
      or light fall off.

My guess is that somehow moisture is getting at your film during the 
exposure or during transport to and from the site.Enroute to the site or 
during exposure would then explain why parts of the frame are affected 
because parts of the emulsion would have lost their improvement from 
hypering. Enroute home not so sure but maybe the developer is similarly 
sensitive to the films exposure to uneven moisture or the moisture is 
clouding the image.

Well, you now know everything I know about Techpan.

Stuart

Thom Iwancio wrote:

>Hey gang, looking for someone to take a look at my latest image and tell
>me what I am seeing.  I am not sure if it is vignetting, uneven
>hypering/processing or just part of the star clouds in Sagittarius.
>There are way to many variables with TP as compared to E200 slides.
>
>The unexposed frames all have even density so I don' think it is the
>hypering or processing.
>
>The image is M8, 45 minutes through a Meade 8" with a Lumicon Easy
>Guider, focal reducer in the f6 position.  Hypering was 96 hrs, 50 C,
>Lumicon 8% forming gas @ 3 psi.  Scan was reduced to 8 bit in order to
>save as a jpg and resized to 1024 x 697 with no other processing.  I can
>email the full 9 meg scan if anyone is interested.
>
>http://home.sc.rr.com/thomiwancio/images/M8TechPan1024.jpg
>
>I still have guiding and focus issues to resolve, but I fell like I am
>slowly making progress.
>
>Thanks in advance,
>
>Thom Iwancio
>Elgin, SC
>www.machunter.org
>home.sc.rr.com/thomiwancio
>
>
>
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>


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