Re: [APML] Light Pillars

["John C. Mirtle" <spampit@shaw.ca>]

Brian,
    If your relative humidity was near 100% when the temperature dropped 26
degrees, then you would have good conditions for ice crystals and light
pillars. Imaging is futile under these conditions, ice crystals scatter a
lot of light producing big halos around stars and low contrast images. I
can't really recommend astrophotography from Canada in the winter. There are
much better places! When it gets that cold, you must advance film *very*
slowly for 2 reasons - first, it can crack. Second, especially with hypered
film, static can develop when you advance the frame causing "lightning
bolts" across your image. While this may be a neat effect the first time it
happens, the novelty quickly wears off.... :-)
    We have normal batteries up here Brian, but we have heaters that are
integrated into the water jacket of the engine block. This makes it easier
to start the engine, unless you have been observing all night and are miles
from a 110v socket!

John Mirtle
Calgary, Ab. Canada

----- Original Message ----- 
From: "Brian larmay" <power_windows4789@yahoo.com>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Sunday, January 11, 2004 9:44 AM
Subject: Re: [APML] Light Pillars


> Hi John,
>
> Your definition of cold and my definition might differ
> a bit.
> Prior to the cold snap, it was around 20 degrees and
> then dropped to -6 which to me is very cold....I
> know..whiney american lol.
> After looking at temps in other Canadian regions, Ive
> seen them recently drop to -20 through -30!
> Yikes man!!
> What kind of car batteries do you use up there<G>.
> Between light pillars, aurora, and clouds, when do yuo
> get a chance to shoot...doesnt your film crack?!?
> Somethins gotta crack in that weather:)
>
> Brian

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