Laser range

[sbk]

On the Wickedlasers.com website, he said that his 45mW laser has a 18 miles range /ubbthreads/images/graemlins/santa.gif /ubbthreads/images/graemlins/icon15.gif

It makes me laugh a lot, because I never see my 100mW laser farther than 3-4 miles!
I don't see the spot on long distance because the beam is brigther than the spot.

What are you thinking about that?

 

[cybersoga]

depends on eyesight doesn't it?!

 

[PhotonWrangler]

At 18 miles, there'd be so much divergence that you'd have a hard time picking up any of the energy without specialized instruments. Not to mention that at that distance over a terrestrial path, earth curvature gets in the way.

 

[Myx]

what ive always found amusing about WickedLasers.... is that they will sell you a "45mW" leadlight for $349.....

OR...... (if you prefer) sell you an OEM 45mW green laser module for $348, and an OEM green laser case for $1...... then put it together for free! /ubbthreads/images/graemlins/wow.gif

 

[Lasernerd]

45mw`s 18 miles is just silly!
now with my 60 watt 532nm yag I have gotten reports during large events that it is seen over 40 miles!

 

[wickedlasers_com]

a photon of light (even at 0.0000000000001 mW) will travel indefinately (infinite miles), so I am just going by a simple linear formula that I have taken the liberty of using of 5mW = 2 Miles as a comparison.

 

[Lasernerd]

[ QUOTE ]
wickedlasers_com said:
a photon of light (even at 0.0000000000001 mW) will travel indefinately (infinite miles), so I am just going by a simple linear formula that I have taken the liberty of using of 5mW = 2 Miles as a comparison.

[/ QUOTE ]


In a perfect condition! (Vacuum)!

 

[sbk]

I always think that over 3-4 miles it isn't possible to see the dot without optical instruments.

But maybe a person that stay at a few meters of the laser, could see the spot with binoculars, because his vision is less disturbate by the laser beam.
So I will certainly try this for confirm!

 

[WildRice]

or if a person was 15miles away and you aimed it at them, how well would they see it. I guess you would need a couple of cell phones and a nice open area.

 

[Lasernerd]

you will be able to see the green flash maybe at that distance

 

[SilverFox]

My Magnum Rescue Laser Flare (5 mW red laser from www.greatlandlaser.com ) has been tested to 20 miles in ideal conditions. It is rated to be visible at night for 4-5 miles.

The purpose of the Rescue Flare is to signal SAR aircraft when you are ship wrecked on the water. Their lens spreads the beam to a line and the SAR people look for the flash.

I would think that if a 5 mW line can be seen at 20 miles, it is not too far to think a 45 mW could be seen at 18 miles...

Tom

 

[The_LED_Museum]

If you're on the receiving end of the beam, then yes, you really can see it out that far.
A few years ago, I shone my 11.6mW green laser pointer to some islands about 20 miles away, and got an "answer" in the form of a flashing light - probably one of those >2,000,000bcp halogen spotlights.

I'm guessing that my green laser beam was by far the brightest light visible on the Seattle skyline at that distance.

 

[Lasernerd]

This is just silly!
You might see a flash of the red or green but I can tell
you a strobe light does just the same,,
so SilverFox you can see a 5mw laser beam line over 5 miles?
I can saythat when I shoot a 5 Watt Argon across the columbia river at the other end about 6 miles the beam is about 500 feet in diameter..
Aircraft can see the flash of the unit than they close on in

 

[SilverFox]

Hello Lasernerd,

I did not do the testing, but if you are interested, you can read about the early prototype testing here.

It is interesting that a single LED light was visible at 3 miles, a Mini Mag 2AA out to 12 miles, and the Rescue Laser Flare was visible to the naked eye at 22 miles. They did not mention the size of the beam, just that it was visible at 22 miles. The proto type green Rescue Laser Flare was still going strong to the naked eye at 30 miles, but that was the furthest distance they were testing to at that time.

Once again, please note that these are ground to air sightings in near perfect conditions.

The beam line of the Rescue Laser Flare is visible at least 30 feet in pouring down rain. It is hardly visible at all in clear air.

Tom

 

[Lasernerd]

Interesting,,
it must be flash and sparkle they are claiming to see.
My Argons look beautiful in the rain or snow for thousnds of feet

 

[PhotonWrangler]

[ QUOTE ]
wickedlasers_com said:
a photon of light (even at 0.0000000000001 mW) will travel indefinately (infinite miles), so I am just going by a simple linear formula that I have taken the liberty of using of 5mW = 2 Miles as a comparison.

[/ QUOTE ]

Ok, but you're not taking into account that -

1) Our visual perception of brightness is nonlinear.

2) The beam density over distance will vary greatly with
the quality of the collimating optics as well as their
alignment during final assembly of the device.

 

[SunSlinger]

Yeah, without someone at the recieving end to see if the "dot" is actually visible,(and how big), without a good telescope & steady mount for the laser, I don't see how the user could see the "dot" at those ranges.

I camp & hike quite a lot & that's one of the main reasons I got my 11.4 AtlasNova unit. For emergency signalling. Before these green ones came out, the red laser signal flares were the only option. Here's another test performed on one of those, which shows just how far they can be seen from the recieving end. A useful tool for emergencies.

http://www.equipped.org/rescuelaser.htm