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. *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
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. > > > *************************************************************************** > PaddleWise Paddling Mailing List > Submissions: paddlewise_at_lists.intelenet.net > Subscriptions: paddlewise-request_at_lists.intelenet.net > Website: http://www.paddlewise.net/ > *************************************************************************** > > *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
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