Re: [Paddlewise] Night Vision

I have used my LED conversions on a couple of Kayak camping trips with mixed
results. A Singlewhite 20,000 MCD LEDs was not visible enough when used in a
standard PFD clip on light, but the RED 6000 MCDs was very effective in the
PFD beacon.

The White and Orange LEDs were excellent as replacement bulbs in a 4 AA
waterproof dive light with a continious burn time exceeding 3 weeks.

See: www.flinet.com/gulfstream/paddle.html

cya
----- Original Message -----
From: Peter Osman <PeterO_at_ambri.com.au>
To: <paddlewise_at_lists.intelenet.net>
Sent: Thursday, June 24, 1999 8:32 AM
Subject: [Paddlewise] Night Vision


> G'Day,
>
> Chuck thanks for pointing to the article - they seem to be having quite a
> debate on the subject. At the end of the article he suggests a simple
> exeriment comparing different colored LED's.  But as well as the color of
> the light what about the intensity rating of the LED? Is a standard LED
> bright enough to read maps by? Is an ultrabright LED too bright? I
followed
> the LED discussion a while ago with a lot of interest in the context of
> night kayaking safety lights. On checking our local "Radiospares" or
> "Farnell" catalogs (Do you have these in the US?) found there was a huge
> difference in the intensity of LED's available, with not much difference
in
> power consumption. A standard red or yellow LED had 5mcd intensity with
> 30degree view angle. I found a range of different colored ultrabrights
with
> an intensity of 250mcd at 25degrees, an ultrabright red "AlGaAs" with
> 2000mcd at 20degrees, an ultrabright yellow "AllnGaPhas" with an intensity
> of 2500mcd at 10degree and an ultrabright green with 3400mcd and 15degrees
> view angle. All of them have power dissipations of about 100 to 150mW. The
> low intensity LED's cost a few cents, the high intensity ones cost a
couple
> of dollars (Australian). Does anyone have experience using such LED's for
> night kayaking? Also I don't really know if it would work but has anyone
> tried using transparent rods as lenses to form sheets of light rather than
> cones - less intensity loss with distance?
>
> PeterO.
>
> On 23 Jun 1999 - Chuck Holst wrote
>
> >The gist of the article, published by the American
> >Association of Amateur Astronomers, is that light
> >intensity, not color, affects night vision most, and that
> >green light is superior to red light because green light
> >does not have to be as bright as red to read charts and
> >instruments. Green also makes many chart colors easier
> >to see.
>
> >I've been trying to figure out how to illuminate our deck
> >compasses for night navigation. Looks like green LEDs
> >might be the way to go.
>
>
>
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