Re: [APML] Poor Blue in 400F?

Hi Alen I tried to shoot it when their was alot of snow on the ground in feb but nothing showed up . my best result was in late sep or oct hope this helps jim

Sincerely,

Jim Renard

From: Alen Koebel <akoebel@rogers.com>
Reply-To: Discussion of Film Astrophotography <astro-photo@seds.org>
To: Discussion of Film Astrophotography <astro-photo@seds.org>
Subject: Re: [APML] Poor Blue in 400F?
Date: Tue, 23 Aug 2005 09:30:05 -0400 (EDT)
>--- Wei-Hao Wang <astrophoto@gmail.com> wrote:
>
> > Hi everyone,
> >
> > I think Alen's case is very rare. I would expect to
> > see A LOT on a 30min/F5.6 shot on M45 with Provia
> > 400F.
> >
> > Look at my picture:
> >
>http://www.ifa.hawaii.edu/~wang/gallery/picutres/m45-2003.htm
> > This is a 85min/F9.4 shot.
>
>Wow. That's impressive. Of course, all of your
>published shots are impressive. (I'm sure you don't
>show us your big mistakes. <g>)
>
>[snip]
> > As Jim pointed out, sky condition may be the reason.
> > In addition, reciprocity failure might be another
> > factor. If the shot was taken in a humid and warm
> > environment, reciprocity failure may be stronger
> > than usual.
>
>That's interesting. I hadn't heard about this
>relationship before. Yes, it was a warm and humid
>August night, whereas the shots on the previous roll
>that did turn out were back in November of last year,
>when it was cold (-8 C) and relatively dry.
>
>I'd be willing to bet light pollution is also a
>contributing factor. You have very little on Mauna
>Kea; I have a lot where I am. A slightly hazy night
>seems to "intensify" the sky glow.
>
>I should try the Pleiades again in October or November
>with the cluster positioned as overhead as possible,
>on a very transparent night (assuming one happens
>near new moon), autoguided for 1 hour and push the
>400F one stop (as per general recommendations here).
>If I don't get a good result then, I'll hang up my
>AP hat! <g>
>
>
>_______________________________________________
>Astro-Photo mailing list
>Astro-Photo@seds.org
>http://seds.org/mailman/listinfo/astro-photo