Author Topic: Head torches and night vision  (Read 4728 times)

Pete McK

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Head torches and night vision
« on: March 25, 2013, 10:29:45 AM »
Came across this really interesting article

http://stlplaces.com/night_vision_red_myth/

captain paranoia

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Re: Head torches and night vision
« Reply #1 on: March 25, 2013, 01:03:47 PM »
I confess that I've always found a very dim white LED to be better for nighttime map reading.  Trouble is, it's hard to find an LED headtorch with the required power control.  I remember seeing a handtorch once, which had a 'find me' setting, which was very, very dim, but just visible in a dark tent or bag.  But I can't remember what make it was, and I've not been able to find it on the 'usual suspects' websites...

Lyle Brotherton

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Re: Head torches and night vision
« Reply #2 on: March 25, 2013, 03:24:24 PM »
Interesting article Pete and I have not found a head torch that can reduce in intensity enough either CP.

I was trained to use red-light at night and experienced exactly the problems this article describes.

As a halfway house I use the diffuser (clear lens) which came with my Silva and clips over the head torches lens and have inserted two thin slips of white polythene, cut from an animal food sack. (I will photo and post this) which works well for me.
“Opinion is the medium between knowledge and ignorance” - Plato

adi

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Re: Head torches and night vision
« Reply #3 on: March 25, 2013, 09:06:03 PM »
I too was trained under red light conditions. If using a hand held torch hold it so the head is pointing into your fingers and adjust your fingers the gap between your fingers to let the right amount of light through. With a head torch stick black electrical tape over the lens of filter. Most black electrical tapes give of a dull red light when you shine a white light through it. It might be a very dull light which you need to get very close to the map to be able to read it, which defeats the pint of a head torch so the solution is to put a pin hole through the tape this should give you enough light to read a map by.
"We do not belong to those who only get their thought from books, or at the prompting of books - it is our custom to think in the open air, walking, leaping, climbing or dancing, of lonesome mountains by preference, or close to the sea, where even the paths become thoughtful." Friedrich Nietzsche

cairngormwanderer

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Re: Head torches and night vision
« Reply #4 on: March 25, 2013, 09:08:52 PM »
Had an interesting discussion with a friend once, who claimed you didn't need a torch as long as you allowed your eyes to acclimatise naturally as night fell. We got a chance to test this soon after, reaching the summit of Stob Choire nam Beith in Glen Coe just as the sun disappeared over the horizon (a common occurrence when I go ice climbing! Must speed up.). We found the descent into Coire nam Beith with the last of the light and were able to see well enough to get almost all the way down to the road before I finally gave up and put my torch on at the last outcrop across the path, which was verglassed, although my mate stuck to it and got down to the road safely. He reckoned it proved his point, although I have to say I would have been able to move a lot faster with a headtorch switched on - and he uses a head torch too(!).
Anyway, I reckon there's not much point in messing about with red or green loghts. Just make sure your batteries are in good order and use your headtorch: it's what we invented technology for. :)

adi

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Re: Head torches and night vision
« Reply #5 on: March 25, 2013, 09:33:39 PM »
I never walk at night using light even in quite wooded areas. Even in the jungle there is just enough light to get around slowly although it is not best practice to move around the jungle at night.
"We do not belong to those who only get their thought from books, or at the prompting of books - it is our custom to think in the open air, walking, leaping, climbing or dancing, of lonesome mountains by preference, or close to the sea, where even the paths become thoughtful." Friedrich Nietzsche

Lyle Brotherton

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Re: Head torches and night vision
« Reply #6 on: March 26, 2013, 09:00:54 AM »
Cairngormwanderer and Adi you are both much more courageous than me.

Before the advent of NVG I was with a group on night-time manoeuvres on the North Yorkshire Moors. It was an overcast sky and the moon I seem to remember was at best a waxing crescent. My party opted not to use head torches and we yomped over the barren landscape to our RV when I was thrown, literally into the air and landed on my back. I had stood on what I thought was a rock to gain a viewing vantage to reccy with my bins on what turned out not to be a rock, but the black patch on a sleeping  Holstein cow. The pandemonium that ensued as the entire heard now spooked started to run wildly across the moorland was as frightening as an op I have ever been on. Needless to say, I always use a head torch (if not using NVG)! 
“Opinion is the medium between knowledge and ignorance” - Plato

adi

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Re: Head torches and night vision
« Reply #7 on: March 26, 2013, 07:29:47 PM »
Lyle it is stories like that that only members of the forces could ever experience and they are always funny. Whilst on patrol at night in Bandit country in Ireland.  We came to a stream that was marked on the map, bordered by a two strand barbed wire fence. We quickly set about securing the obstacle and I was to clear it. So I hoped over the fence and was shocked to find myself in free fall. After a short time I hit the riverbed rucksack first like a beached turtle, through the inky darkness I saw dark figures in free fall above me then I heard the dull thud and responding splash as my team mates followed me. What the map had not showed us was that this stream had cut into the bank undercutting the fence and that the stream bed was 20 feet below the bank. Being in Bandit country we were being highly tactical but now there are 4 lads from our patrol brick, rucksack down in this stream trying to suppress grunts, gowns and giggles. To this day I wounder if anyone had been close by and heard this commotion what they wondered about what went bump in the night. 
"We do not belong to those who only get their thought from books, or at the prompting of books - it is our custom to think in the open air, walking, leaping, climbing or dancing, of lonesome mountains by preference, or close to the sea, where even the paths become thoughtful." Friedrich Nietzsche

captain paranoia

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Re: Head torches and night vision
« Reply #8 on: March 27, 2013, 12:13:02 PM »
A friend of mine once squatted down behind a rock at night to have a pee.  Imagine her surprise when the rock got up and walked away...

Baaaa...

boogyman

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Re: Head torches and night vision
« Reply #9 on: March 27, 2013, 07:47:23 PM »
That was a polite rock then, CP -- I know several rocks that would have sat still and enjoy the show...  ;D

Callum

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Re: Head torches and night vision
« Reply #10 on: April 02, 2013, 07:48:06 PM »
Spent years stumbling about in red light and following the rear-axle differential illuminated on the vehicle in front of me in the convoy. Nowadays only ever use dimmed white light (still stumble about allegedly;)  )

adi

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Re: Head torches and night vision
« Reply #11 on: April 03, 2013, 10:12:44 PM »
I was in a covert hide located on the edge of the park, playing fields over looking Derry NI. When a rather attractive young adult left a group of other young adults messing about and playing football on the playing field and walked straight toward us. Once here feet were no more than a foot from us she stopped dropped her jeans and undergarments squatted down facing us and proceeded to relieve herself. She was so close she splashed our optical equipment. We were so shocked to get such an eye fall that it took every ounce of control not to laugh. 
"We do not belong to those who only get their thought from books, or at the prompting of books - it is our custom to think in the open air, walking, leaping, climbing or dancing, of lonesome mountains by preference, or close to the sea, where even the paths become thoughtful." Friedrich Nietzsche