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(meteorobs) [IMO-News] Re: Leonids Video
------- Forwarded Message
Date: Wed, 10 Nov 1999 21:35:36 +0100 (MET)
From: Sirko Molau <molau@informatik.rwth-aachendot de>
To: imo-news@egroups.com
Subject: [IMO-News] Re: Leonids Video
Hello Craig,
> Questions : Which lens would best for the showers?
> How large a field is optimal?
that depends mainly what you intend to do with your video observations.
Wide angle systems give usually the most 'impressive' video recordings
since you record on average brighter meteors. However, the spatial
resolution is not as good as for a normal or tele system. So, if you want
to obtain the radiant position or do double station observations, a
smaller field of view is preferable.
In this year we expect much more fainter meteors than in 1998, which is
another reason to give priority to a good limiting magnitude. This is why
I would suggest to use a normal or moderate tele lens, for example a fast
50 mm lens.
A field of view of 20 deg with limiting magnitudes of 8 to 9 mag for stars
should be ok.
> Where is the best place to aim the system?
You should neither look directly at the radiant (pointlike meteors are
hard to detect) nor too far away from it (long & fast meteor trails). A
fov some 30..40 deg west of the radiant is probably a good choice.
> It can and will be mounted on a driven scope.
For three reasons I will not do so with my own camera:
* the mounting need to be accurately aligned with the pole to prevent
drifting stars, which my meteor detection software would have
difficulties to cope with
* not to drive your camera means that you always look at the same volume
atmosphere under identical conditions (extinction, etc), which should make
it easier to derive flux rates from the counts
* you do automatically observe meteors in different positions around the
radiant, which gives a better radiant plot from single station data
Best regards,
Sirko Molau
- ----------------------------------------
Sirko Molau -- Video Commission Director
International Meteor Organization
e-mail: video@imodot net
WWW : http://www.imodot net/video
- ----------------------------------------
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