From: Ian Stirling
Subject: Re: Make infrared goggles inexpensively (like $10!!!)
Date: Wed, 18 Sep 2002 10:51:24 +0000 (UTC)
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NNTP-Posting-Date: Wed, 18 Sep 2002 10:51:24 +0000 (UTC)
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In sci.physics William J. Beaty wrote:
> I was paranoid about them when I first started messing with
> this. But I never experienced any afterimages, nor the famous
> burning pain of UV corneal damage (snow blindness.) The goggles
> have glass lenses, and the filters are polycarbonate, so they do
> take out lots of UV. The only trouble is that the sun looks like
> a dim red disk when viewed through the goggles. It might be harmful
> to stare fixedly at it and focus the invisible part of the IR
> output on my fovea. So I don't. These goggles probably aren't
> so great as a mass-produced toy, but smart hobbyists probably
> won't hurt themselves.
Obtain a prism that will pass IR. (or at least near IR)
Arrange so that you can look through it at the sun, from a distance, so
you can observe various wavelengths by moving your head.
(a mirror may be handy to reflect the prisms output into a horizontal
Now, get a dense neutral-density filter, and compare transmission at
various points in the prisms output with your filter, to see if it passes
any green, or if what you are seeing is truly 'IR' (in the loosely defined
sense of bits of the spectrum that are almost always overwhelmed by
wavelengths to which the eye has a greater response)
http://inquisitor.i.am/ | mailto:firstname.lastname@example.org | Ian Stirling.
Things a surgeon should never say:
Better save that for the autopsy.