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(meteorobs) Re: Leonids Meteor Colors
>I don't know enough about this topic myself: perhaps one of the photography
>experts can shed more light, but will reciprocity failure affect the apparent
>colour recorded on film?
>
>Reciprocity failure means that the usual photographic rule - that opening the
>aperture one stop is equivalent to doubling the exposure time - does not work
>for *very* long or *very* short exposure times. The point for colour
>photography is that reciprocity failure affects the different colour layers
>in the film differently. The net result is a shift in colour balance at very
>short or long exposures.
>
>On the other hand, even though the camera shutter was open for a long time,
>the actual meteor is only being photographed for a short time. On the third
>hand, for any given point on the meteors trail, the exposure is very short.
>
>Mind you, none of this would explain the _change_ in recorded colour. I'm
>getting rapidly out of my depth here. Help!
>
>David Cross
>
>
>>Date: Thu, 25 Nov 1999 11:23:12 +0200
>>To: Meteor Observing Mailing List <meteorobs@jovian.com>,
>> Dr Peter Brown <peter@danlon.physics.uwodot ca>
>>From: Ilan Manulis <ilan@trendline.co.il>
>>Subject: Leonids Meteor Colors
>
>...stuff clipped out
>
>>As it turns out, all meteor trails up to a certain time have a distinct
>>deep red-purple color. From that time on, they all have green-blue color.
>>As I took the pictures in succession all through the night, this fact is
>>evident.
>
>
>
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