Gareth,
I've calculated that I get about 1 to 3 "good" astronomy shots per roll
of film, on average. I've been doing astro stuff for a couple of years
now, and my success rate is improving, at least.
I'm using 800 film on the planets because of the need to get as short an
exposure as possible. The reason is that the planets are in in the part
of the sky where they move the "fastest". On my negatives the stars &
planets are "trailed" even at 8 second exposures with a 50mm lens (wider
lenses can go longer). Normally I shoot Kodak LE 400 (formerly PJ400)
for astro shots, and if it have another clear night and run out of 800
that's what I'll go with.
Skyglow and/or light pollution is almost always green in my experience.
The few astro slides I've taken show this clearly.
The green in the center of the pic is due to one or all of: skyglow at
twilight, light pollution, maybe the zodiacal light, and vignetting of
the camera lens. I partially corrected the green in photoshop, and given
enough time there is much more that could be done to the shot ;-) I kind
of like all the colors, though!
Don't get much aurora down here in Houston, TX ;-)
-Dick
p.s. links to astro & other pix at my home page:
http://home.houston.rr.com/dtlocke/index.html
Date: Fri, 3 May 2002 16:32:57 +0100
From: "Gareth.J.Martin" <g.j.martin@xxxxxxxxxxxxx>
Subject: Re: [OM] planet pic bracketing
Wow! That's a lot of over exposed photographs. I've never used ISO 800
for astrophotography as the grain is just too coarse, and there is
really not much, if any, visible difference between ISO 400 and ISO 800.
Sky and Telescope confirmed this a few years back in one of its issues
when they reviewed films for astrophotography, its a good article which
I dare say you've read.
Personally, I always find that ISO 200 is perfect for most needs,
especially general photography of the night sky. As for exposure times
it is a case of experience and bracketing. On a dark night with ISO 200
and a 28mm Zuiko f2.8 (at f2.8) a 5 second exposure will record the sky
and keep sky glow to a minimum from my home location. Here in Bristol,
UK though that's impossible!
Its a great picture though. Is the green at the centre of the exposure
light pollution? I can't say I've ever seen green light pollution
before! Its just the last time I took a picture of a planetary
conjucnction (2000 April 6/7) was also one on the biggest auroral
storms for some time wand auroral glow was present on the image with
the planets. Needless to say there was only two images of the
conjunction the rest was used on the auroral display!!!
Best Wishes,
Gareth.
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