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Re: (meteorobs) Leonids from Arizona and question
In a message dated 11/25/99 1:47:05 PM Eastern Standard Time,
direland@drdale.com writes:
> I looked close at my negatives, I know some meteors went through the
> field but they were just too faint. The camera and 400 film was on a
> driven mount and I was surprised to see it caught good images of deep
> sky objects like the Rosette nebula and the large faint Barnard's Loop
> near Orion, just no meteors, bummer. I will try 800asa next time.
Whats happening here is the usual astrophotography trade off.
To get more of the sky you need the wider lens. With the wider lens quick
objects need to be brighter to record. You got the Rossette and Barnard's
Loop because they stood nice and still for your camera. But a meteor wasn't
in the sky long enough for the photons to build up in the emulsion. While I
can't say what magnitude the meteor must be to see, you may see one or more
if you look at the negative w/ a high power loupe.
Another thing, I don't know if it was brought up, is reciprocity failure,
which means the longer you leave the aperature open the less sensitive the
film becomes. So a 400 ASA film may be down to ASA 20 after a certain amount
of time. I don't have the times nor films memorized but Kodak sells a little
manual with information like this for all their films.
Kevin K
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