Re: night vision

[William Beaty <billb@ESKIMO.COM>]

On Wed, 9 Jan 2002, Bernard Cleyet wrote:

> It had been advertised earlier (I missed buying it at a sl. higher price), so
> I was prepared. Fortunately I tried it out, as that one was defective, or all
> are unsatisfactory.   I found it difficult to operate the P/S and keep the
> image in the view field (the HV "lasts" < one sec. / squeeze).

The ones I bought will stay lit for about 3-5 minutes per squeeze, if used
outdoors at night.  In a room with normal lighting, the eyepiece flashes
bright green for about a second (normal room lighting is too much for the
thing.)  The instructions say that the gain is 10,000 - 15,000.  One
interesting part: if you block the lens entirely and then view the
phosphor screen in a dark room, you can see lots of sparkles.  Must be
single photons!  From thermal?  Or maybe from cosmic rays.

> So I purchased
> a dig. 8 mm with IR CCD.   It appears to have the same or better sensitivity
> with the added advantage of greater optical gain (18X), and memory.  Of course
> it's 6.2 X price.

A couple of years ago I built one of these by using a $90 bare-board CCD
camera and a $150 video display from a camcorder (viewscreen about 1"
across, with an eyepiece lens).  With an IR filter across the camera lens
it made a great "IR scope", but it doesn't see much when outdoors at
night.  I put the camera-card in a small plastic box attached with
velcro, so I could either attach the camera to the front of the video
display (like an IR scope), or pull it loose and stick it inside
equipment.   I think my camera came from Marlin P. Jones surplus.

  bare-board CCD cameras ($40 and up)
  http://www.mpja.com/list.asp?dept=124


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William J. Beaty                                  SCIENCE HOBBYIST website
billb@eskimo.com                                  http://www.amasci.com
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