Re: [APML] Speeding up film with cold weather

[Jerry Lodriguss <jml@astropix.com>]

>I figure it refers to a films lack of ability to
>continue to record photons at a constant rate.

That's it.




>My results so far show that Supra recorded well over
>twice as much light in a 330 minute exposure as it did
>in a 140 minute exposure. This film is a slow, but
>steady collector of light.


How did you measure twice as much light?



>That really surprised me, as I assumed 150-180 minutes
>would be my upper limit. I can occaisonally see 5.6
>magnitude stars here, but I'm 50 years old. I'd guess
>6.0+ would not be out of the question for younger
>eyes.

 From the darkest site, 60 to 90 minutes at f/8 would be about max, and 
that's only 120 to 180 minutes minutes at f/11, and you are at f/10.

Perhaps the T/stop of your scope is much slower than the f/stop. Maybe you 
are closer to T/16.

Of course, you can also go past the skyfog limit and keep building density 
in the film, but loosing faint stuff also.

Five and a half hours and 400 ISO film with good reciprocity failure at 
f/10 is just causing a mental disconnect on my part.

Jerry









Astronomical photography: http://www.astropix.com




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