While listening to some 365 days of Astronomy PodCasts while grading today, I listened to one on Red Light and Night Vision. The author has the podcast as an article on her website located at http://www.alicesastroinfo.com/ . She sites a US Navy study from the 1980's to lead off the article: "Red light has been used because it is well established that subsequent dark adaptation is faster than with any other color. However, the magnitude of this advantage depends on the intensity of the adapting light. … The measure that has typically been used to show this phenomenon is the time required to detect pinpoints of light at absolute scotopic threshold–that is, the individual’s maximum sensitivity. Although this is undoubtedly of great importance at times, it is probably true that in most practical situations the observer is required to operate at something less than maximum sensitivity and to detect targets quite different from spots of light." Alice further quotes a website located here on the myth of the Red light: http://stlplaces.com/night_vision_red_myth/ "Experimentation shows a L.E.D. with a peek around 700nm seems to work best (perceived as a deep red). Note that red may be fatiguing to the eyes." Alice also states that based on the US Navy's stud, one must be fully dark adapted for a red light to benefit and that using a red light source helps "but only if you’re going stargazing in an extremely dark place. If you’re stargazing from within a city, you will likely never be somewhere that dark." I invite anyone to look at the sites, they are interesting I think. So what color light do you use when you observe in your backyard? Is it red, is it white or something else? What light do you use in the field if you need one? Does using a red light really help at a site like SPOC or a backyard where there is so much white light coming into the field from the surrounding neighborhood? Can such sites truly allow for full dark adaptation? I have my opinion but would like to see what others both do and what their opinions are.
I use a flashlight with a red photo filter taped over the lens; the filter is covered with tape except for a silt, so that it's pretty dim. It works fine for me. Unfortunately, my computer screen tends to reduce my night vision, even when I have it dimmed with a red tint that's available with a couple of astronomy programs. But I feel sure red light is the best way to preserve night vision. -- Joe --- On Sun, 8/29/10, Jay Eads <jayleads@gmail.com> wrote: From: Jay Eads <jayleads@gmail.com> Subject: [Utah-astronomy] Red Light Myth To: utah-astronomy@mailman.xmission.com Date: Sunday, August 29, 2010, 3:46 PM While listening to some 365 days of Astronomy PodCasts while grading today, I listened to one on Red Light and Night Vision. The author has the podcast as an article on her website located at http://www.alicesastroinfo.com/. She sites a US Navy study from the 1980's to lead off the article: "Red light has been used because it is well established that subsequent dark adaptation is faster than with any other color. However, the magnitude of this advantage depends on the intensity of the adapting light. … The measure that has typically been used to show this phenomenon is the time required to detect pinpoints of light at absolute scotopic threshold–that is, the individual’s maximum sensitivity. Although this is undoubtedly of great importance at times, it is probably true that in most practical situations the observer is required to operate at something less than maximum sensitivity and to detect targets quite different from spots of light." Alice further quotes a website located here on the myth of the Red light: http://stlplaces.com/night_vision_red_myth/ "Experimentation shows a L.E.D. with a peek around 700nm seems to work best (perceived as a deep red). Note that red may be fatiguing to the eyes." Alice also states that based on the US Navy's stud, one must be fully dark adapted for a red light to benefit and that using a red light source helps "but only if you’re going stargazing in an extremely dark place. If you’re stargazing from within a city, you will likely never be somewhere that dark." I invite anyone to look at the sites, they are interesting I think. So what color light do you use when you observe in your backyard? Is it red, is it white or something else? What light do you use in the field if you need one? Does using a red light really help at a site like SPOC or a backyard where there is so much white light coming into the field from the surrounding neighborhood? Can such sites truly allow for full dark adaptation? I have my opinion but would like to see what others both do and what their opinions are._______________________________________________ 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
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.
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
I agree that most Red Lights these days are too bright for Astronomy. Brightness is a selling point and for the vast majority of people (non-astronomers) consider brighter better it's is easy to see why bright lights are so popular. I used to have an adjustable red light that was perfect but alas it has long since bitten the dust. All the new ones are too bright IMHO. At SPOC I don't think my eyes ever get close to dark adapted so I'm not sure how much it really matters. There are so many obnoxious white lights around from buildings and cars if you are not in the observatory that I don't think red. purple, blue or white makes a difference, it's just etiquette. Intensity would be an issue though, not color. Bright lights are just annoying. In the military we frequently used blue lights instead of red and they seemed to do the trick as well as the red filters. In general I don't think color is anywhere near as important as intensity. However, right or wrong I'm am inclined to use a colored light and red light is not questioned on an astronomy field, I'm not sure what reaction I'd get with my blue light from the majority of astronomers. Bob -----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
If anyone here uses a mini maglite there is a thing called the IQ switch. I found it at harbor freight. It has 100 % 50 % and 25 % intensity plus two different pulse settings. It just screws on the back. I think it was $6.99. With a red filter or rubylith this would probably be ideal. ________________________________ From: Robert Taylor <rob.taylor@digis.net> To: Utah Astronomy <utah-astronomy@mailman.xmission.com> Sent: Mon, August 30, 2010 7:38:46 AM Subject: Re: [Utah-astronomy] Red Light Myth I agree that most Red Lights these days are too bright for Astronomy. Brightness is a selling point and for the vast majority of people (non-astronomers) consider brighter better it's is easy to see why bright lights are so popular. I used to have an adjustable red light that was perfect but alas it has long since bitten the dust. All the new ones are too bright IMHO. At SPOC I don't think my eyes ever get close to dark adapted so I'm not sure how much it really matters. There are so many obnoxious white lights around from buildings and cars if you are not in the observatory that I don't think red. purple, blue or white makes a difference, it's just etiquette. Intensity would be an issue though, not color. Bright lights are just annoying. In the military we frequently used blue lights instead of red and they seemed to do the trick as well as the red filters. In general I don't think color is anywhere near as important as intensity. However, right or wrong I'm am inclined to use a colored light and red light is not questioned on an astronomy field, I'm not sure what reaction I'd get with my blue light from the majority of astronomers. Bob -----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 _______________________________________________ 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
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
I agree with Kim here, either green or red works the key is brightness. Using the Grim I don't ever get truly dark adapted, seems if you can read the computer screen it is probably to bright. There does seem to be faster recovery of dark adaption when red light is used. I used the grim with sun reading glasses once, because I brought the wrong ones, it did seem to help with computer screen brightness. SPOC is not a great place for dark adaption, but it is great location for public star parties.
Reading star charts seems to also require a certain brightness that may not help dark adaption. Goto systems help with this. I imagine the Navy nowadays relies on radar and any lookout either uses night vision equipment or is not exposed to much ambient light while using binoculars. I use a flashlight with a red photo filter taped over the lens; the filter
is covered with tape except for a silt, so that it's pretty dim. It works fine for me. Unfortunately, my computer screen tends to reduce my night vision, even when I have it dimmed with a red tint that's available with a couple of astronomy programs. But I feel sure red light is the best way to preserve night vision. -- Joe
--- On Sun, 8/29/10, Jay Eads <jayleads@gmail.com> wrote:
From: Jay Eads <jayleads@gmail.com> Subject: [Utah-astronomy] Red Light Myth To: utah-astronomy@mailman.xmission.com Date: Sunday, August 29, 2010, 3:46 PM
While listening to some 365 days of Astronomy PodCasts while grading today, I listened to one on Red Light and Night Vision. The author has the podcast as an article on her website located at http://www.alicesastroinfo.com/. She sites a US Navy study from the 1980's to lead off the article:
"Red light has been used because it is well established that subsequent dark adaptation is faster than with any other color. However, the magnitude of this advantage depends on the intensity of the adapting light. ⦠The measure that has typically been used to show this phenomenon is the time required to detect pinpoints of light at absolute scotopic thresholdâthat is, the individualâs maximum sensitivity. Although this is undoubtedly of great importance at times, it is probably true that in most practical situations the observer is required to operate at something less than maximum sensitivity and to detect targets quite different from spots of light."
Alice further quotes a website located here on the myth of the Red light: http://stlplaces.com/night_vision_red_myth/
"Experimentation shows a L.E.D. with a peek around 700nm seems to work best (perceived as a deep red). Note that red may be fatiguing to the eyes."
Alice also states that based on the US Navy's stud, one must be fully dark adapted for a red light to benefit and that using a red light source helps "but only if youâre going stargazing in an extremely dark place. If youâre stargazing from within a city, you will likely never be somewhere that dark."
I invite anyone to look at the sites, they are interesting I think. So what color light do you use when you observe in your backyard? Is it red, is it white or something else? What light do you use in the field if you need one? Does using a red light really help at a site like SPOC or a backyard where there is so much white light coming into the field from the surrounding neighborhood? Can such sites truly allow for full dark adaptation? I have my opinion but would like to see what others both do and what their opinions are._______________________________________________ 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
Years ago I did some spelunking in a handful of remote caves. Most of my companions used carbide head lamps - not too bright but reliable. I used a 6-volt electric lamp that used odd batteries that I've only seen in outdoor stores. On one trip to a cave in Nevada my headlamp was initially brighter than the carbide lamps but when the battery began losing power and it became dimmer than the carbide lamps my companions all told me I should change the battery. I was determined to get all the life out of the expensive batteries that I could so I ignored them and kept going with my ever dimmer light. I noticed that even when my light was very feeble I could still see just fine. In fact, I could see detail better with my very dim light than I could when I looked at surfaces illuminated by my friends' lights. I think that in addition to the issue of what works better for dark-adapted vision there is also a contrast issue. For awhile after I purchased my Ultima 2000 I tried using my computer and a cheap program, SkyMap Pro, to drive it. The red light setting on the program was still much too bright. I picked up some scrap red Plexiglas from Delvie's in SLC (very cheap) and cut it to fit over my laptop monitor, fixed in place with a couple of pieces of Velcro. That cut the brightness enough that it didn't affect my night vision anymore than a dim red flashlight. I recommend it for anyone who uses a computer at night, even in red mode. Kim
I will try that, Kim! Sounds great. I'm also a caver from way way back (think late '60s, early '70s). I was very much a carbide fan, because if you carry extra carbide, a bag for the used stuff and water, you can keep the light going for many hours. I liked the tactile sensation of relighting: you cup your hand over the lamp, let carbide gas build up in it, thumb the lighter wheel as you get your hand out of the way and pop, light! Thanks for the memories, Joe --- On Mon, 8/30/10, Kim <kimharch@cut.net> wrote: From: Kim <kimharch@cut.net> Subject: Re: [Utah-astronomy] Red Light Myth To: "'Utah Astronomy'" <utah-astronomy@mailman.xmission.com> Date: Monday, August 30, 2010, 10:28 AM Years ago I did some spelunking in a handful of remote caves. Most of my companions used carbide head lamps - not too bright but reliable. I used a 6-volt electric lamp that used odd batteries that I've only seen in outdoor stores. On one trip to a cave in Nevada my headlamp was initially brighter than the carbide lamps but when the battery began losing power and it became dimmer than the carbide lamps my companions all told me I should change the battery. I was determined to get all the life out of the expensive batteries that I could so I ignored them and kept going with my ever dimmer light. I noticed that even when my light was very feeble I could still see just fine. In fact, I could see detail better with my very dim light than I could when I looked at surfaces illuminated by my friends' lights. I think that in addition to the issue of what works better for dark-adapted vision there is also a contrast issue. For awhile after I purchased my Ultima 2000 I tried using my computer and a cheap program, SkyMap Pro, to drive it. The red light setting on the program was still much too bright. I picked up some scrap red Plexiglas from Delvie's in SLC (very cheap) and cut it to fit over my laptop monitor, fixed in place with a couple of pieces of Velcro. That cut the brightness enough that it didn't affect my night vision anymore than a dim red flashlight. I recommend it for anyone who uses a computer at night, even in red mode. Kim _______________________________________________ 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
A bit off-topic... Joe, my spelunking days were in the mid 70's. In fact, my first serious excursion was to Nutty Putty, where John Jones died last year. I'm pretty sure that I know exactly where he got stuck. It was a scary place. I had been doing a lot of construction work that year, so I was in great physical shape, thin and wiry. Otherwise, there's no way I could have got through that tight spot. Kim -----Original Message----- From: utah-astronomy-bounces+kimharch=cut.net@mailman.xmission.com [mailto:utah-astronomy-bounces+kimharch=cut.net@mailman.xmission.com] On Behalf Of Joe Bauman Sent: Monday, August 30, 2010 11:33 AM To: Utah Astronomy Subject: Re: [Utah-astronomy] Red Light Myth I will try that, Kim! Sounds great. I'm also a caver from way way back (think late '60s, early '70s). I was very much a carbide fan, because if you carry extra carbide, a bag for the used stuff and water, you can keep the light going for many hours. I liked the tactile sensation of relighting: you cup your hand over the lamp, let carbide gas build up in it, thumb the lighter wheel as you get your hand out of the way and pop, light! Thanks for the memories, Joe --- On Mon, 8/30/10, Kim <kimharch@cut.net> wrote: From: Kim <kimharch@cut.net> Subject: Re: [Utah-astronomy] Red Light Myth To: "'Utah Astronomy'" <utah-astronomy@mailman.xmission.com> Date: Monday, August 30, 2010, 10:28 AM Years ago I did some spelunking in a handful of remote caves. Most of my companions used carbide head lamps - not too bright but reliable. I used a 6-volt electric lamp that used odd batteries that I've only seen in outdoor stores. On one trip to a cave in Nevada my headlamp was initially brighter than the carbide lamps but when the battery began losing power and it became dimmer than the carbide lamps my companions all told me I should change the battery. I was determined to get all the life out of the expensive batteries that I could so I ignored them and kept going with my ever dimmer light. I noticed that even when my light was very feeble I could still see just fine. In fact, I could see detail better with my very dim light than I could when I looked at surfaces illuminated by my friends' lights. I think that in addition to the issue of what works better for dark-adapted vision there is also a contrast issue. For awhile after I purchased my Ultima 2000 I tried using my computer and a cheap program, SkyMap Pro, to drive it. The red light setting on the program was still much too bright. I picked up some scrap red Plexiglas from Delvie's in SLC (very cheap) and cut it to fit over my laptop monitor, fixed in place with a couple of pieces of Velcro. That cut the brightness enough that it didn't affect my night vision anymore than a dim red flashlight. I recommend it for anyone who uses a computer at night, even in red mode. Kim _______________________________________________ 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
On 30 Aug 2010, at 17:21, Joe Bauman wrote:
http://news.yahoo.com/video/dallascbs11-15750646/fighter-jet-for-sale-216587...
Ha! That thing drinks as much in one minute as mine does in one hour. patrick :)
On 8/30/10, Patrick Wiggins <paw@wirelessbeehive.com> wrote:
On 30 Aug 2010, at 17:21, Joe Bauman wrote:
http://news.yahoo.com/video/dallascbs11-15750646/fighter-jet-for-sale-216587...
Ha! That thing drinks as much in one minute as mine does in one hour.
Yes, but it will get you to Jerry Foote's place in 20 minutes... ;o)
Here is an article regarding red versus green: http://www.astromax.org/kniffen.htm After reading that, I started using a green light for reading charts and a red light for everything else. In order to read anything with the red light, I have to turn the intensity way up but even with the lowest intensity level, I can read easily with the green light. At truly dark sites, I use a light from Rigel that has both red and green lights and has a dimmer knob. At public star parties, I usually use a somewhat brighter red light (it also includes a green laser pointer). For breaking down, my favorite is a red headlamp. Fletch
While listening to some 365 days of Astronomy PodCasts while grading today, I listened to one on Red Light and Night Vision. The author has the podcast as an article on her website located at http://www.alicesastroinfo.com/. She sites a US Navy study from the 1980's to lead off the article:
"Red light has been used because it is well established that subsequent dark adaptation is faster than with any other color. However, the magnitude of this advantage depends on the intensity of the adapting light. The measure that has typically been used to show this phenomenon is the time required to detect pinpoints of light at absolute scotopic threshold-that is, the individual's maximum sensitivity. Although this is undoubtedly of great importance at times, it is probably true that in most practical situations the observer is required to operate at something less than maximum sensitivity and to detect targets quite different from spots of light."
Alice further quotes a website located here on the myth of the Red light: http://stlplaces.com/night_vision_red_myth/
"Experimentation shows a L.E.D. with a peek around 700nm seems to work best (perceived as a deep red). Note that red may be fatiguing to the eyes."
Alice also states that based on the US Navy's stud, one must be fully dark adapted for a red light to benefit and that using a red light source helps "but only if you're going stargazing in an extremely dark place. If you're stargazing from within a city, you will likely never be somewhere that dark."
I invite anyone to look at the sites, they are interesting I think. So what color light do you use when you observe in your backyard? Is it red, is it white or something else? What light do you use in the field if you need one? Does using a red light really help at a site like SPOC or a backyard where there is so much white light coming into the field from the surrounding neighborhood? Can such sites truly allow for full dark adaptation? I have my opinion but would like to see what others both do and what their opinions are._______________________________________________ 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
participants (10)
-
Chuck Hards -
Dunn, David -
erikhansen＠thebluezone.net -
Fletcher Gross -
Jay Eads -
Joe Bauman -
Kim -
Nate Jackson -
Patrick Wiggins -
Robert Taylor