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RE: (meteorobs) lens for Meteors
My "all sky" setup is about 50% of the sky using a 36 in.
security mirror and second hand 2x extender on a 8mm wide
angle old Videocon lens from the 1950's on a 0.06 lux CCD.
This gives about a 1st to 2nd limiting magnitude.
Unfortunately my big city sky is sometimes not much better
than that so I have not gone to a photomultiplier as the
Europeans have.
The meteor observing guide books say go for the largest
optical gain (lowest f ratio) because there are many more little
meteors. That is go for the smallest f lens ( largest diameter )
you can afford first, then choose the largest FOV (shortest
focal length) in that range.
The camera will usually produce enough heat, if pointed upward,
to keep the dew off. If it is not pointing upward as mine is not, you
might want some heat tape if you have power for it.
----------
From: ykChia
Sent: Monday, October 04, 1999 1:54 AM
To: meteorobs@jovian.com
Subject: (meteorobs) lens for Meteors
Hi all:
I have a b/w 12 volt DC watec 902H 'C' mounted camera and intend to
use this ( recording to a Hi-8 handycam) for the coming Leonids at
Jordan. Need help on what is the best lens focal length should I
use tocompromise between limiting magnitude and FOV.
Also will dew be a problem in near desert conditions?
rgds
yeong kwong Chia
--
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