Re: [APML] Meteor Photography Questions

["Alson Wong" <alsonwong@earthlink.net>]

----- Original Message -----
From: "Jerry Lodriguss" <jml@astropix.com>
To: <astro-photo@seds.org>
Sent: Wednesday, October 31, 2001 12:01 AM
Subject: Re: [APML] Meteor Photography Questions


> Alson,
>
> Shoot wide open!  If you want meteors, that's the only way to go.
>
> You simply can NOT make up for the reduced aperture and reduced ability to
> record faint meteors by exposing for a much longer time before reaching
skyfog.
>
> You have two separate exposures going on here at the same time, the meteor
> and the sky background. The meteor exposure is essentially a flash
exposure
> that will be governed strictly  by aperture and f/ratio and film speed.
The
> length of the exposure has nothing to do with recording an individual
> meteor. You could shoot all night at f/16 based on your thinking, but you
> probably wouldn't capture any.
>
> The only possible argument for long exposures is that you want to capture
a
> lot of meteors on one frame, but to do that you should be thinking of
using
> a film with a LOT of reciprocity failure, so you can still expose long,
but
> do it wide open.

Yes, recording a lot of meteors on one frame was what I was thinking about
with P1600, which, according to Robert's tests, has a two-stop loss in speed
after two minutes.  At 1600, I can go 15 minutes at f/2.8 with my 28mm or
20mm lenses (which would be better, 28mm or 20mm?).  I know that my best
chance for recording the faintest meteors is to use the 50mm wide open at
f/1.8 (4 minutes), but shooting at f/2.8 would make it more convenient in
that I could start and stop the exposures on both cameras at the same time.
I may try some exposures at both f-ratios.
--
Alson Wong
Riverside Astronomical Society
     http://www.rivastro.org/
Visit my Web page at:
     http://home.earthlink.net/~alsonwong/index.htm


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