From:	Paul Jonathan Adam <Paul@********.DEMON.CO.UK>
Subject:	Re: Renegade's Gun Mod's
Date:	Sat, 15 Apr 1995 15:27:21 GMT

> > Not necessarily. To crank up brightness you grab as much spectrum as you
> > can, which is why night-vision goggles (image intensifiers) are sensitive
> > in the near IR as well as to visible light.
>
> IR sensitivity is separate from intensifying the ambient light,
> though the two technologies can be combined. And, actually, the color we
> see the best is yellow, not green (green is second). Naturally, this is
> because the sun's luminescence curve puts out more yellow light.

Generation II and III image intensifier tubes pick up the visible spectrum
and also some of the near IR: no seperate band, just the "past red and
not visible". That's one of the reasons aircraft and helicopters being
flown by pilots in NVGs need the cockpit displays modified: conventional
lighting put out too much IR and flared the goggles, so you couldn't
read your instruments. It's also why the NVGs I used had a IR illuminator
which clipped to the front, as a sort of flashlight invisible to the naked
eye (sadly not to any of the enemy who had NVGs as well, though).

> Green is a good color to discern contrasts, which is why it was
> used for the first computer terminals (and are now used for military
> night-vision). This is why the tube is coated with a green
> phosphorescent coating; not the other way around. Green was designed in,
> not a result of the design.

Oops. Should have remembered you can choose your phosphorescense colour...

> Full color image intensification remains unlikely due to the low
> light levels and different behavior of various colors. The index of
> refraction for blue et. al. is different enough as to be relatively useless.

C'mon, you could rule out three-quarters of the rule book like that! :-)

> > I'd guess about the size of a TV camera - a studio one - if it was 'optical'
>
> An effective optical image intensifier would have a lens at least
> 30 cm in diameter, which would give a rough intensification factor of
> 3600. You couldn't use fiber optic arrays or synthetic apertures because
> that would require signal processing and ruin the effectiveness for a mage.

As I said - a box about three feet high and wide, four or five long, weighing
at least half a ton, so the magician doesn't try to strap it to his
face and walk around with it :-)

--
When you have shot and killed a man, you have defined your attitude towards
him. You have offered a definite answer to a definite problem. For better or
for worse, you have acted decisively.
In fact, the next move is up to him.

Paul J. Adam paul@********.demon.co.uk