Why Green Laser Pointers?

[JerryM]

I haven't read all the GLP thread, but I wonder if so many people use it. What do you use it for other than briefings, instruction? I guess that enough, but I am surprised to see so many post on that subject.

Excuse my ignorance in that matter. (Notice that I qualified what I was ignorant about so "other threads" would not be affected. /ubbthreads/images/graemlins/grin.gif)

Jerry

 

[flashfan]

I think green laser pointers are more for astronomy and/or outdoor purposes, especially the higher-powered ones. In my opinion, even the 5mW units are brighter than necessary (or safe?) for regular use indoors at presentations and lectures.

The green laser was perfect for pointing out Mars recently, and over the next two weeks, it could come in handy to identify the unusual occurrence of five planets visible at the same time during the early evening hours. Also great for pointing out constellations like the little dipper, etc.

For me, part of the "allure" may be the "gee whiz" factor. I can't explain it, but I'm just somehow drawn to portable lighting devices like laser pointers and bright flashlights/spotlights. I can't help but smile with awe and delight everytime I turn on a green laser pointer, the SureFire M6, and the McCulloch x990, to name just a few.

 

[lasercrazy]

Yeah greenies are great for astronomy and impressing the neighbors with a lightshow. /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/bowdown.gif /ubbthreads/images/graemlins/popcorn.gif /ubbthreads/images/graemlins/cool.gif

 

[PeterW]

5mW green are FAR too powerful for indoor use! They should only be used by suitably trained/qualified people.

Two reasons for green, that result in their ideal use for astronomical pointing use.
1) Rayleigh scattering in the atmosphere is much stronger for shorter wavelengths (explains why the sky is blue). The scattered light is preferrentially directed back along the beam, making it useful for pointing.
2)Green is the colour that the eye is most sensitive to, this allows the brightest amount of light for the least optical power.

Hope this helps. Explains why you can't do the same trick with a red laser pointer! I am sure blue would work due to 1), but you would need more power due to 2), and the fact that blue lasers are MOST expensive also rules them out.

PEterW

 

[JerryM]

Many thanks. I had really wondered why the seemingly great interest is such a thing. I also did not realize the power of the light.

Thanks again,
Jerry

 

[PhotonWrangler]

[ QUOTE ]
flashfan said:
For me, part of the "allure" may be the "gee whiz" factor. I can't explain it, but I'm just somehow drawn to portable lighting devices like laser pointers and bright flashlights/spotlights.

[/ QUOTE ]

Same here... it's the same reaction that I had when I first saw a red laser pointer, only more so because the green wavelength is so much more visible. Being able to see the beam without needing lots of smoke or fog is also really neat. It feels more like a real laser because of this and inspires more awe than a pointer that just places a little red dot on a wall.

 

[powernoodle]

So you can see the beam in the night sky?

So where can I get one of these powerful green lasers? I need a new toy. /ubbthreads/images/graemlins/thumbsup.gif

thx

 

[PhotonWrangler]

[ QUOTE ]
powernoodle said:
So you can see the beam in the night sky?

So where can I get one of these powerful green lasers? I need a new toy. /ubbthreads/images/graemlins/thumbsup.gif

thx

[/ QUOTE ]

Yes, the beam is visible in a very dim room or in the night sky, especially if there's a lot of humidity in the air.

You can find them here...