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Re: night vision optics

Subject: Re: night vision optics
From: Walter Knapp <>
Date: Sat, 15 Mar 2003 01:19:49 -0500
I realized I should probably warn everybody. If you go into Ebay and do
a search on "night vision" you will find lots and lots of binoculars
that claim night vision. These often have nothing more than a red filter
in them, if that. Traditional night binoculars have very large front
lenses for their magnification and provide at most a few multiples of
actual light. A Gen 1 scope is providing 35000X light intensification, a
Gen2 is 65000X or so. The night vision stuff we are talking about has a
light intensification tube or tubes, run by a high voltage circuit off
batteries. You don't actually look through them, the front lens focuses
on the input end of the intensification tube where the light is
converted into electrons that the high voltage accellerates and your
eyepiece is focused on the display end of the tube that the electrons
hit. The difference between the Gen 1 and Gen 2 is that the Gen 2 has a
   charged plate in the tube consisting of many fine micro channels,
allowing greater electron acceleration and thus brightness. There is no
optical path for light through them, it's electrons.

None of them seem to be able to use rechargable batteries. Mine runs off
two lithium camera batteries. Of course you can find the batteries in
bulk on Ebay too. Mine will run for 10 - 20 hours on one set of
batteries. One thing it has that helps there is a proximity sensor on
the back end so it can sense when you bring it to your eye. It goes into
a low power mode with the tube off when it's not at your eye. That's
settable, you can set it to run continuous if using it mounted on a
camera or a video camera.

Walt







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