Green laser pointers

CSG

CSG

Joined
Dec 15, 2007
Messages
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I bought one a few years ago to use while giving astronomy talks outdoors. It's the perfect way to show people the object you're talking about.

How useful do you think an item like this is for nighttime signaling? The beam shoots way up there like a long skinny light sabre. The thing looks like a pen with a pocket clip and runs on two AAA alkaline batteries.

It would be easy enough to put in a shirt pocket but are these really effective signaling devices if you should get yourself in a survival situation hoping to signal rescuers? I carry all the normal stuff including a whistle, signal mirror, and LED flashlight but it occurs to me that shooting a beam up with either Morse code SOS or just series of three flashes might be pretty good. Being green, it would be visible in NVG's.
 
If someone is looking for you, it could be useful. Otherwise, people probably wouldn't know what to think.
 
Well, if there are 'planes in the air when you are in trouble, you can probably be sure of 'rescue' quite quickly.

I've just got one myself, a couple of weeks ago. 50mW green, runs on a CR2 lithium (so good for packing away until it's needed knowing the cell will still work).

Lithium's are also good in the cold, better than alkalines, however... the green laser pointer might not be. They are quite susceptible to cold causing them to stop working temporarily. Treat it like a Bic!

Given how bright the things are, and how small, I think it's a useful addition to the kit myself. But don't point it at the 'planes!

Edit: just changed the power on my laser - I got confused I've looked at so many over the last month
 
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I suppose a quick safety note is in order...

Anything over a few mW can be dangerous to your eyes. Much more than that and even a reflection could immediately burn a dot onto your retina which could easily be permanent.

Don't take chances! Read up on the dangers before playing with the things.

By the way, my 50mW cost about $25 - these things are cheap!

Green LASER's appear much, much brighter than the same power red LASER's and the beam can usually be seen even in daylight from scattering off moisture and dust.
 
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foxyrick said:
I suppose a quick safety note is in order...

Anything over a few mW can be dangerous to your eyes. Much more than that and even a reflection could immediately burn a dot onto your retina which could easily be permanent.

Don't take chances! Read up on the dangers before playing with the things.

By the way, my 80mW cost about $20 - these things are cheap!

Green LASER's appear much, much brighter than the same power red LASER's and the beam can usually be seen even in daylight from scattering off moisture and dust.
Click to expand...



Check this out for info:
cheap green lasers



Stay sharp,
desmobob
 
CSG - some interesting info on lasers as signal devices can be found here.

www.greatlandlaser.com

These lasers are specifically designed for signaling. I don't have one, but the idea is interesting.
 
I just checked the output on mine. It is <5mw. Don't know what that means (powerful/weak?) but as I said, it was purchased specifically for evening astronomy talks to point the way in the night sky. It works so well for that purpose that it just seems like it could be a useful signaling device.
 
These green lasers are so powerful that some of them can even burn, look up some of the videos on youtube
 
Seems mine is on the weaker end of what's available. I bought 5-6 years ago.
 
5mW is generally considered 'safe' although I still wouldn't want it pointed in my eye. It would probably take deliberate, continual and painful efforts to cause harm with it.

The output on the Chinese made greenies is usually (a) exaggerated and (b) includes the infrared used to make the green (an IR laser excites a crystal which frequency-doubles it to green). Good green LASER's have IR filters to take out the IR from the beam.

There's a bit of over-panic (in my opinion) about the IR. Some say that, because you can't see it, it can get into your eye without the pupil responding and you don't know you're being damaged. This is correct. However, the IR coming from these green LASER's is quite diffuse. It's not in a concentrated beam like the green. So, it's nowhere near as big a problem as some say it is. In my opinion, IANAE!

Bottom line is anything more than 5mW really should be treated with caution, not used indoors where reflective surfaces are close, or even outdoors to point at something close by.

And yes, it's fun popping balloons and lighting things with the more powerful ones (generally 100mW+)
 
Well, I may add it to my kit, especially if my boys are with me. It makes showing them the night sky much easier. And, perhaps, it may have some value as a signaling device if needed.
 
Back in '06, I turned Marty Simon onto these when he saw mine during the Basic Course I took. Since then, Aggie secretly bought him one through me and my crotch has not been safe from lasering.

Seriously, they make teaching celestial navigation easy!
 
There is lots of good safety info on the greatland site. suffice to say lazers are way safer than most people would like to believe. Just as the sun will not instantly burn out your eyes.

as for using a regular lazer for signaling, hold one on taget at a white wall at 100m. then tell me you can hit a pilot's eye at 2.5 miles. the reason the greatland one works is that it is a fan. although the green ones can sometimes be seen from distance with NVG, if your SAR has them. I belive there are some more testing info on doug ritter's site, well thought out with good control of test variables.
 
i have one and contemplated signaling. One thing I haven't tested, which some of you here may have, is its horizontal visibility. In other words, if the lazer is pointed straight up how far off to the side can one stand before the beam becomes invisible, or will it?

Suppose I'm in a canopy of trees with only a small opening to reach the sky, can rescuers standing on a hill top, or on the ground, some ways away, see the beam?

just curious
 
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