Archived posting to the Leica Users Group, 1997/11/16

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Subject: Re: Many are Cold, Few are Frozen
From: "" <>
Date: Sun, 16 Nov 1997 13:17:54 -0500

>In astronomy they sometimes use special cameras in which the emulsion is
>chilled with liquid nitrogen. I was under the impression that film became
>more sensitive (presumably to both visible light and cosmic rays) at very
>low temperatures. Do any of the amateur astronomers on the LUG know
>anything about this? 

I'm not sure about what you mentioned, but the super-cooled instruments 
are used in astronomy are typically composed of electronic sensors, not 
film emulsions.  Examples of this are in the Hubble Space Telescope's 
near infared camera and spectograph sensor, which is cooled by liquid 
nitrogen.  I would imagine that cooling film emulsions would make them 
less, not more sensitive to light, since chemical reactions are usually 
inhibited by such low temperatures.