Red LED Flashlights?

[Mdinana]

Obviously the Gerber - love it, btw, use it in the morning when I'm up before my wife.
Inova X5 in red, I think they might have another in red
SF with a filter or red LED, or the Aviator series (I got mine on the CPF MP)
Streamlight has their aviator-esque version w/ red LEDs as well.
I think cabela's or Bass Pro shop also have in-house aviator-esque lights
Pentagon MOLLE light w/ filter
Proton Photon or Proton Pro
Zebralight 501r or 51r (I think that's the newest one)
Gerber Recon
Fenix has filters for their lights.
Petzl has a few red filter headlights.
Smith and Wesson "Galaxy" light has dual white/red
I think there are numerous brands of the "keychain" light (photons and fauxtons) that come with red LED's - I've got several attached to gear and my body armor.

I've been on a red LED kick too these last 2 weeks. Can't wait for my ZL's to ship! Wishing I'd brought all my red lights...

As an aside, Amazon has the NVG photon for $8, and the Photon Pro for $38.

 

[subwoofer]

I have this one - http://www.dealextreme.com/p/ultraf...-k2-red-led-flashlight-1-18650-2-cr123a-20333 Nice and bright

I also have this DX torch and the KaiDomain version http://www.kaidomain.com/ProductDetails.aspx?ProductId=9347

The DX one will run best on an 18650 and slightly dimmer on 2x16340. The KD one is 18650 only as it is direct drive.

If you want something dimmer the Skywatcher Dual beam Astronomy torch is good with variable brightness, but is much dimmer and uses 5mm LEDs

 

[dcbeane]

flashmenow this is what I get when I click on your link:

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[Vox Clamatis in Deserto]

The use of the 'night vision' green is that it's at a wavelength that stimulates the rods very strongly, and at low levels the medium wavelength cones are very slightly stimulated. This means that it engages the magnocellular system, but also the parvocellular system, which is responsible for our perception of fine detail, and prevents the eye from focusing to infinity because it's activated. It's much easier to see fine detail and read small text when using one of the NV green (turquoise actually) lights.

Them 25 cent words are way over my head but your explaination does agree with my experience. I have several 'military' lights with both red and green emitters. I do occasional backyard astronomy and visual satellite tracking. I can work, walk and find my beverage with a much dimmer green light than red light. And yes, I realize that my eyes are much more sensitive to the green light than the red light in the first place.

Red light presbyopia is often mentioned in aviation physiology courses. Night myopia causes many visual astronomy buffs to have a separate eyeglass prescription for night work.

Here's a classic web analysis of using red light to maintain night vision (it cites and has been cited by CPF in years past):

http://stlplaces.com/night_vision_red_myth/

Aircraft cockpits decades ago featured red lighting but this has largely disappeared in recent designs from what I can see. Red map lights are probably still offered as an option on airliners, things like this seem to stay in the certification regulations in some countries long after they are no longer in common use.

 

[dcbeane]

From what a buddy in Iraq tells me, its not just that red maintanes night vision, red is also harder for the enemy to see at a distance.
I would like to compare "night vision green" to red at a distance, and see which can be seen more easily.... but I don't have any military night vision green lights.
I don't think CREE actually makes Red LEDs. They are buying those from another source and branding them CREE.
That is what I was told at a shareholder meeting in the last couple years....unless this is a new development.

 

[MrBenchmark]

I don't usually play this card in online forums (mostly because it usually elicits derision and insults), but I earned my PhD in perceptual psychology in 2005, and have been teaching sensory perception, cognitive psychology, and physiological psychology (among others) for the last five years in the University of California system, and for the last year in the Cal State system.

Hi B0wz3r, I'm interested in your experience with astronomy, NVG lights, and how it affects your scotopic vision. There are as you well know a bunch of reasons amateur astronomers like red lights, some of them seem really outdated to me, some of them still relevant:
- less affect on scotopic vision (assuming you can actually see what you need without using so much light you blow it anyway)
- less impact on film, so when people have a shutter open, you don't risk their image as much (Oh wait - does anyone use film anymore, aren't CCD's more sensitive to red than blue?)
- everyone does knows this is best! (How can everyone be wrong!!!!!111!)
- fear of the delay in regaining full scoptopic vision.

Lol, that sum it up pretty well?

Anyway, do you have any experience with how rapidly your scotopic vision recovers after using a dim NVG light? Have you been in a situation where you can be fully dark adapted and tried this? (Just asking - it is very difficult in many normal environments to ever be fully dark adapted - you understand I know.) I do know from firsthand experience that for my eyes anyway, it takes about 15 minutes to get decent dark adaptation, and 30-45 minutes before it's really there. People doing visual deepsky observation are sometimes pushing their vision for all it's worth, so you can understand why people are so conservative about this, particularly when it takes so long to recover.

Anyway, just wondered if you knew more about this - some of the things I've read about it left me unconvinced that the visual tasks they tested were much like what happens at the eyepiece. (But what do I know?) I totally agree about trying to read stuff in dim red light - it is horrible.

Oh, back on topic, uh, +1 on the photon pro. Ether the red or white lights on it are just ridiculously dim. The HDS lights (not cheap) are also quite dim, although you might find them too bright when your eyes are dark adapted. (I do anyway.)

 

[B0wz3r]

Hi B0wz3r, I'm interested in your experience with astronomy, NVG lights, and how it affects your scotopic vision. There are as you well know a bunch of reasons amateur astronomers like red lights, some of them seem really outdated to me, some of them still relevant:
- less affect on scotopic vision (assuming you can actually see what you need without using so much light you blow it anyway)
- less impact on film, so when people have a shutter open, you don't risk their image as much (Oh wait - does anyone use film anymore, aren't CCD's more sensitive to red than blue?)
- everyone does knows this is best! (How can everyone be wrong!!!!!111!)
- fear of the delay in regaining full scoptopic vision.

Lol, that sum it up pretty well?

Yep. As was mentioned above, for purely protecting your dark adaptation, red does work best. If you're actually trying to do anything that requires any kind of reasonable visual acuity, then the NVG works best. That's why the military uses it in their low light targeting and detection systems, instead of red.

Anyway, do you have any experience with how rapidly your scotopic vision recovers after using a dim NVG light? Have you been in a situation where you can be fully dark adapted and tried this? (Just asking - it is very difficult in many normal environments to ever be fully dark adapted - you understand I know.) I do know from firsthand experience that for my eyes anyway, it takes about 15 minutes to get decent dark adaptation, and 30-45 minutes before it's really there. People doing visual deepsky observation are sometimes pushing their vision for all it's worth, so you can understand why people are so conservative about this, particularly when it takes so long to recover.

It has been a long time since I was in a situation where I was fully dark adapted, probably not since last summer, up in the Sierras camping on the Merced river. That being said, in low light conditions (close to, but not fully scotopic), it only takes me a couple or three minutes for my adaptation to come back after using my NVG light. But, I also turn it on in low and let it ramp up, rather than start it on high. I also use a lower voltage battery, a 2032 in it instead of 2x2016, so it can go lower and doesn't go nearly as high that way.

Going from regular vision to nearly scotopic takes me about 15 minutes or so too... in those situations I find the .2 lumens on something like my Quark AA to be more than bright enough. The .6 lumen setting on my ZL SC50w+ is almost too bright sometimes in those situations.

Anyway, just wondered if you knew more about this - some of the things I've read about it left me unconvinced that the visual tasks they tested were much like what happens at the eyepiece. (But what do I know?) I totally agree about trying to read stuff in dim red light - it is horrible.

Oh, back on topic, uh, +1 on the photon pro. Ether the red or white lights on it are just ridiculously dim. The HDS lights (not cheap) are also quite dim, although you might find them too bright when your eyes are dark adapted. (I do anyway.)

I think your intuition about the tasks that have been tested in low light vision not being similar to actual observing conditions is correct. One of the crazy contradictions about this is that most of the people I know in our local club can see the color of different stars even when they're fully scotopically adapted. That leads me to think either that they're not fully scotopically adapted as they think, in order to be able to differentiate different colors of stars, or that they're viewing objects of sufficient magnitude to overcome the scotopic adaptation at just the point where they're seeing the star on their retinae. It would be a small enough area that the total effect wouldn't really be noticeable consciously, or the light wouldn't be intense enough to invoke Whytte's reflex (the reflex where our pupils contract suddenly on exposure to bright light).

I also agree that very dim red light is essentially useless, except for gross navigation. I'd rather have a dim NVG or white light for that purpose. I've been considering a light that will go ultra low, less than .1 lumen, but I'm still deciding how I want to proceed on this. My wife uses red lights mostly when we're observing, and the NVG photon I gave her for things like reading charts and logging observations. I use mine for pretty much everything. I'm considering getting her one of the new red ZL headlamps that are coming out soon, as she is still pretty traditional about that, and I know that she'd appreciate it, and so would other club members. I still get some negative reactions to my NVG light at club events sometimes.

For observing though, I'd say that at the eyepiece, you really do want to be as close to scotopic as possible, so red is best for when you're actively working at your scope. My wife is the master at this... she finds stuff with her 10" manual dobsonian that most other people in the club have to use a computer controlled motor drive to find. She's become known for her ability to do that. I am the helper really, fetching food and equipment and stuff like that; I'm simply too ham-handed with the scope to even keep anything centered in the eyepiece... in general though, the NVG meets my needs for both observing and working pretty well. If I was doing the finding and being the primary scope operator, I'd probably want red, but I think NVG would be fine for that too, as long as you didn't get it too bright. My next step is going to be to experiment with using both a red and an NVG light.

 

[MrBenchmark]

Yep. As was mentioned above, for purely protecting your dark adaptation, red does work best. If you're actually trying to do anything that requires any kind of reasonable visual acuity, then the NVG works best. That's why the military uses it in their low light targeting and detection systems, instead of red.

I thought the NVG were also less affected by this - blinding your helicopter pilot who's flying by NVG is bad, or so I'm told! (Not that I'd know from first hand experience, I'm lucky they let me drive a CAR! )

That being said, in low light conditions (close to, but not fully scotopic), it only takes me a couple or three minutes for my adaptation to come back after using my NVG light. But, I also turn it on in low and let it ramp up, rather than start it on high. I also use a lower voltage battery, a 2032 in it instead of 2x2016, so it can go lower and doesn't go nearly as high that way.

Thanks - a few minutes would be a reasonable tradeoff in many situations.

I think your intuition about the tasks that have been tested in low light vision not being similar to actual observing conditions is correct. One of the crazy contradictions about this is that most of the people I know in our local club can see the color of different stars even when they're fully scotopically adapted. That leads me to think either that they're not fully scotopically adapted as they think, in order to be able to differentiate different colors of stars, or that they're viewing objects of sufficient magnitude to overcome the scotopic adaptation at just the point where they're seeing the star on their retinae. It would be a small enough area that the total effect wouldn't really be noticeable consciously, or the light wouldn't be intense enough to invoke Whytte's reflex (the reflex where our pupils contract suddenly on exposure to bright light).

That sounds right, because I can definitely vouch for this myself, switching from albireo, a blue and gold double star over to say the veil nebula, the veil is obviously monochrome. Some planetary nebula have a distinct blueish / greenish color. (They mostly glow in OIII light.) These tend to be relatively small as well, not points like stars, but less than an arc minute anyway.

I also agree that very dim red light is essentially useless, except for gross navigation. I'd rather have a dim NVG or white light for that purpose. I've been considering a light that will go ultra low, less than .1 lumen, but I'm still deciding how I want to proceed on this. My wife uses red lights mostly when we're observing, and the NVG photon I gave her for things like reading charts and logging observations. I use mine for pretty much everything. I'm considering getting her one of the new red ZL headlamps that are coming out soon, as she is still pretty traditional about that, and I know that she'd appreciate it, and so would other club members. I still get some negative reactions to my NVG light at club events sometimes.

I know what you mean about club events. I am pretty sure at some clubs you'd get less flack over a one of the new red Olight M20S than you would over your ridiculously faint NVG photon! (I am reasonably sure that with a modicum of dark adaptation, you could probably drive a car at low speeds pretty safely with the Olight! But gee, it's red so it must be OK!)

I highly recommend the ZL headlamps. I will probably buy one of the new H31r's when they come out. I've got the prior model, the h501r, and I really like it and use it heavily. The UI takes some getting used to. It is pretty natural for me to turn it on to low now, but honestly I had to make myself just practice with it for a couple of days until the action became muscle memory. I find it to be extremely useful at my scope, at least when I use any light at all.

For observing though, I'd say that at the eyepiece, you really do want to be as close to scotopic as possible, so red is best for when you're actively working at your scope. My wife is the master at this... she finds stuff with her 10" manual dobsonian that most other people in the club have to use a computer controlled motor drive to find. She's become known for her ability to do that. I am the helper really, fetching food and equipment and stuff like that; I'm simply too ham-handed with the scope to even keep anything centered in the eyepiece... in general though, the NVG meets my needs for both observing and working pretty well. If I was doing the finding and being the primary scope operator, I'd probably want red, but I think NVG would be fine for that too, as long as you didn't get it too bright. My next step is going to be to experiment with using both a red and an NVG light.

Thanks for confirming this, and feel free to post about what you notice about red vs. NVG. I'd be interested in hearing about it. I really appreciate hearing from someone with:
- professional experience on the matter
- actual first hand experience at astronomy
- no real axe to grind

BTW, earlier you mentioned that under dim red light we tend to focus to infinity. Thanks for mentioning that, that explains an issue I didn't understand with my multi-focal contacts. (My soon to be ex-multi-focal contacts.) These things are duds for me - they are AWESOME at near and medium ranges. In daylight, they are slightly blurry at infinity, but they are tolerable, particularly given how good they are everywhere else. And they are comfortable. UNFORTUNATELY, at night, under dim light at infinity, they show double. I can't read street signs, stuff like that. Just not safe to drive while wearing them, but once I reach medium range, I can see OK with them in the dark. However, in my observatory dome, about 10 feet away from me, there's a little red LED on a power supply - and it ALSO was doubled when I looked at it, even though in daylight, at that range it would be in perfect focus with these lenses. But what you said explains this.

Anyway, if your wife can get used to the ZL UI, the little headlamps are just genuinely fantastic in my opinion. (I don't find the UI to be BAD - it is just that it is not natural, you have to press-hold, then double-click to get the lowest light level. In practice this is really no less convenient than just clicking the light on - but it is not what you'll do the first few dozen times you use the light...) I use mine every evening I go out to my observatory. Like I said, I bet I end up with a new one too. It is also pretty comfortable to wear. (OK, my SF saint minimus is better and more comfortable, but it's white light, and it well, cost like it is better too...) I'm not quite sure how many red LED lights I have - I have quite a few. The ZL and an old red SF L1 are the two I grab every night. (The L1 is mostly too bright - it's mainly for critter detection and avoidance! )

 

[JA(me)S]

Anyway, if your wife can get used to the ZL UI, the little headlamps are just genuinely fantastic in my opinion. (I don't find the UI to be BAD - it is just that it is not natural, you have to press-hold, then double-click to get the lowest light level. In practice this is really no less convenient than just clicking the light on - but it is not what you'll do the first few dozen times you use the light...)

With the new ZL H51r, or H31r you long press (.6 sec.) to get to low. And then double click to toggle between L1 and L2 - but it remembers the last level chosen in each main level after turn off and through battery changes. Much easier.

 

[MrBenchmark]

With the new ZL H51r, or H31r you long press (.6 sec.) to get to low. And then double click to toggle between L1 and L2 - but it remembers the last level chosen in each main level after turn off and through battery changes. Much easier.

Thanks for explaining that - I missed that. That is much better. I think I'll definitely need one of these.

 

[B0wz3r]

Mr. B, I've got a couple of ZL's right now, an SC50w+ which is my primary EDC, and an H51w, both of which I love dearly. My only beef with the H51w is that it works poorly with a cap; I feel naked without a baseball cap on, and using the clip on my H51w on the bill is a half-assed solution at best. (I've got one of the new Spark ST5's on order from SBflashlights though...). I'm sure I could teach my wife to use the ZL interface without too much trouble. The only thing I think she'd complain about is it being 'too complicated'.

About professional feedback; we live in the SF bay area, and Alex Fillipenko has given talks at our club before (The Mt. Diablo Astronomical Society), and my wife goes to his talks on campus at Berkeley when she gets the chance. If I can, the next time he gives a talk, I'll see if I can ask him a few questions about his experiences with observing lights. Geoff Marcy sometimes comes to our club events too, so I can try and ask him when I get the chance.

We've had a lot of bad weather here lately, and the last three regular observing nights have all been cancelled due to poor conditions. My wife is going to the Golden State Star Party in July, so I don't know when we'll be able to get to our next club event, but I'll see what I can do about getting opinions. I was actually thinking about volunteering to give a talk about this whole topic at our next club event, and getting some feedback in advance would be a good idea for that.

Anyway, I'd love to hear more about what your observing and equipment. We're still pretty much entry level amateurs, but the mirror in my wife's scope needs a professional cleaning and/or replacement; we don't have the funds right now to upgrade to a better model, but we've been considering making our own. I think we should focus on getting better eyepieces than going for sheer size... there is an older couple in our club that have a 24" truss dobsonian, and the thing is simply awesome... but buying something like that, let alone even just building one ourselves, is out of our time and resources capabilities right now.

 

[CKOD]

night vision red/green/etc threads are always interesting. But what Ive been seeing in this thread also echoes what

would seem to indicate.

Night vision is most sensitve to a cyan/green color, Day vision the most sensitive to a green/yellow color. If you wanted to totally avoid bleaching night vision receptors, then stuff in the 600nm+ range would affect them the least, while still somewhat providing illumination for the photopic receptors, though. A yellowy green from 555-575 nm would stimulate the photpic receptors fully while not affecting the scotopic receptors as much as a deeper green would.

I also find it interesting that low pressure sodium lamps emit around the 589nm band, which means its not so harsh on night vision, vs mercury or metal halide lamps throwing off light which the night vision receptors would be sensitve too.

 

[calipsoii]

I know Barbarian long ago found his red LED light, but this thread has morphed into a general red LED discussion, so why not keep the ball rolling?

First off, B0wz3r you write an impressive technical post, very interesting reading!

For anyone who already has a light powered by 5mm red LED(s) and is willing to do a little modding, I can vouch for the deep red LED's offered by LEDSupply. No, I don't work there or advertise for them and I'm not going to link them directly. The difference between their offering and a standard red LED is the wavelength: 660nm vs. the standard 620-630. I've used them in a couple A2 rings and it's a gorgeous red tint without a hint of pink. Makes the 620nm offered by SF/ZL/Inova look orange in comparison.

I ripped apart a cool white Fauxton ($0.50), replaced the LED with one of the deep red ones ($0.60), popped in a $2.00 3V CR2032 coin cell (2.8V max means it's a little overdriven but not much) and voila! A gorgeous deep red keychain light for under $5! Makes a good weekend project.

 

[MrBenchmark]

About professional feedback; we live in the SF bay area, and Alex Fillipenko has given talks at our club before (The Mt. Diablo Astronomical Society), and my wife goes to his talks on campus at Berkeley when she gets the chance. If I can, the next time he gives a talk, I'll see if I can ask him a few questions about his experiences with observing lights. Geoff Marcy sometimes comes to our club events too, so I can try and ask him when I get the chance.

Oh cool, I really Dr. Fillipenko's talks! /jealous (I saw him on TV onetime give a talk about thermodynamics - he used a webber BBQ grill to demo it. I love those grills, so I thought that was just awesome!)

I'd be interested to know if he actually ever looks through an eyepiece. There is no reason to do this professionally. It's neat, it's fun, and I love it, but for serious data collection of most astronomical objects, the Mark I eyeball is pretty much obsolete. A correctly applied CCD will capture more than your eye ever will, even connected to a gigantic telescope. However, people who ride horses mostly don't do it because it's the fastest way from point A to point B, either. Mostly.

Anyway, I'd love to hear more about what your observing and equipment. We're still pretty much entry level amateurs, but the mirror in my wife's scope needs a professional cleaning and/or replacement; we don't have the funds right now to upgrade to a better model, but we've been considering making our own. I think we should focus on getting better eyepieces than going for sheer size... there is an older couple in our club that have a 24" truss dobsonian, and the thing is simply awesome... but buying something like that, let alone even just building one ourselves, is out of our time and resources capabilities right now.

Since we're really derailing this topic, I'll PM you with my email address and a link to my observatory website.

 

[BARBARIAN-X]

Wait, the Proton Pro UV isn't an NVG light... it'll be more like a blacklight really... But, that might be cool too! I've always wanted a UV flashlight just that reason... It might actually work well as a night vision light. I don't remember if it's LRI or Inova that makes them, but they do make a UV coin cell light they call the 'scorpion killer' or something like that... cause spiders and scorpions really light up under UV so it's easy to find 'em and squish 'em. Fortunately, where I live, there's no scorpions, but we do tarantulas!

Sorry... I'm rambling... it's late and I just spent the last three hours chopping firewood, and now Capt. Morgan and Coke are having their way with me! LOL...

NVG not UV...D'oh!
Just got the lights last week and they are nice. The white/red Proton Pro is very useful but obviously the Proton UV isn't. At least it's a good spider light, I hate those *******s! The Proton Pro's red led appears to get too bright at the highest setting as I have had sleeping prisoners move in their sleep when I hit them with it. At lower levels it was fine but for simplicity I have just been using a CMG Infinty for this purpose because it's one brightness setting is lower than the Proton Pro's highest. The CMG is also toddler approved as I have been testing it out on my sleeping son and he hasn't stirred. lol I'll have to order a NVG light to test out...any suggestions?

 

[kramer5150]

Fun thread....
I use a SF-A2 with red LEDs. Its dim enough that I can snoop around the house without waking up my wife or kids. Its actually a little too bright if I just shine it around, but I ceiling bounce it and it completely preserves my night vision. I was with my brother in law 2-3 months ago and we were looking at Jupiter and its moons, using the A2 to preserve our vision.

Awesome little nightstand light

Sammy approves this thRED

 

[RedLED]

night vision red/green/etc threads are always interesting. But what Ive been seeing in this thread also echoes what

would seem to indicate.

Night vision is most sensitve to a cyan/green color, Day vision the most sensitive to a green/yellow color. If you wanted to totally avoid bleaching night vision receptors, then stuff in the 600nm+ range would affect them the least, while still somewhat providing illumination for the photopic receptors, though. A yellowy green from 555-575 nm would stimulate the photpic receptors fully while not affecting the scotopic receptors as much as a deeper green would.

I also find it interesting that low pressure sodium lamps emit around the 589nm band, which means its not so harsh on night vision, vs mercury or metal halide lamps throwing off light which the night vision receptors would be sensitve too.

In my gel sample book, there is a turquoise blue with similar numbers.

 

[RedLED]

New Red Flashlight Announcement - RED SUN DROP!

I would also like to announce that I recently got a Red Sun Drop from McGizmo!

Floody, and three levels of red. Perfect for me to navigate backstage at things with three cameras.

I have been testing the other colors for night use with my photo gel sample book. This, and something to use as a gel holder will change the color of any light. If you have an L1, you can use the F04. The Mag accessories work good, too.

To test, just use some gaffer tape like we do in photography. If you can take the light apart, just put the gel inside against the lens. Gel is made to work huge lights for motion picture, television, and photogtaphy production, so heat is not a problem.

The Red Sun Drop is fantastic!!!

Good luck,

RL

 

[B0wz3r]

Re: New Red Flashlight Announcement - RED SUN DROP!

Dude, I'd be happy with just a regular Sun Drop!!!

 

[RedLED]

Re: New Red Flashlight Announcement - RED SUN DROP!

As a lover of Red LED lights, I found this one: Xenopus Electronix 660 Ultra Red Flashlight. (I did not link it, but you can search for it).

Seems OK, does any one have one? For $60.00, worth a try?