I built 15 of these a while back for a family reunion that was at a Monte Cristo Star party. They were dim like we would want. I assume you could vary the resistor and make them dimmer. http://www.dma.org/~wagner/led.htm Thanks. Dave -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Kim Sent: Sunday, August 29, 2010 8:46 PM To: 'Utah Astronomy' Subject: Re: [Utah-astronomy] Red Light Myth I use red because my only other choice is white. I use a magalite with a red filter and keep it VERY dim. Not to offend anyone, but I find that many SLAS members at star parties are using red lights that are WAY too bright. And, I've never seen a red LED that wasn't too bright, either. I've learned solely by experience that the brightness is a bigger factor than the color. (I don't read as much as you, Chuck.) There have been times when I forgot my favorite flashlight and used newspapers or paper from a brown paper bag as a filter on a white flashlight, and as long as I kept it dim it was fine. Kim -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Chuck Hards Sent: Sunday, August 29, 2010 8:30 PM To: Utah Astronomy Subject: Re: [Utah-astronomy] Red Light Myth In my backyard, the color of my flashlight doesn't matter. There is enough ambient light for it to never be truly dark. Never. I've read studies for decades that variously claim that it's not the wavelength of light (color) that is as important, as the intensity. There are die-hards in both camps. I use red out of habit, although I have used a dim green light in the past when it was all that was available, and it didn't seem to have an adverse affect on my night vision. Whichever color gives you the greatest "comfort factor" is probably best for you. _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com