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Should I buy this?

keiran420

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I have been looking around the web for a nice replacement green laser pointer, (if you have any cheap sites, link me up), I found this one..
green laser

Im looking at the 'handheld 300mW (FDA) 0.5 Kg 121.20 pound one.

Im confused on the spec sheet tho.., it says 'Range in darkness (m)
500-1000'

is that half a kilometer or the best part of a thousand miles ??!

surely it would be more than a kilometer in darkness, my 250mw cheap chinese one that looked nowhere as good as this did more than that!

A thousand miles, surely not...
 

Sigurthr

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Lasers have no range, it is a misnomer (false fact). How long you can see the the beam or how far away you can see the dot from depends on the atmospheric conditions, not the laser itself. If your laser beam is aimed up at the sky and manages to not hit any interstellar objects, it will go on past our galaxy. Photons don't just stop without hitting something.

That being said I just ordered the 100mW model myself and am looking forward to it. There have been some great reviews of these lasers done recently.
 

keiran420

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That is confusing then, what are anyone elses verdict on this laser..?

I dont wanna spend that kinda money on a pen that wont even guarantee a kilometer in darkness >.>

Somthing sounds off.
 

Sigurthr

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I understand you want to verify my answers because you are new and are trying to be thorough and spend money wisely, but...

Look this isn't my opinion, it is simple physics. Laser light goes on forever until stopped by matter. You can't guarantee a distance for a laser, it doesn't work that way and is purely a marketing ploy. The factors involved are:

-rayleigh scattering (which is based on the wavelength, the size of the particles of air and the particles suspended in the air, and the angle between the viewer and the laser beam)
-altitude above ground level
-local atmospheric conditions (weather),
-light pollution level (ambient light level)
-the human eye's sensitivity to the particular wavelength (which is affected by the next item)
-the current visual state of the observer (photopic vs. mesopic vs. scotopic vision)
-the exact output power of the laser
-the beam specs of the laser (divergence, beam diameter, spacial mode, operational mode).

Have you ever bought a walkie talkie? Ever notice on the box it says something like "Range: 2miles". Know how it NEVER actually works at 2 miles range? Radio waves are electromagnetic waves just like light. You can't guarantee a distance. The radio waves from the walkie talkie go on forever as well, the intensity is just too low for the receiver to detect at the distance though. Another example: I've used a 100Watt transmitter and held a conversation with someone across the world 11,000 miles away. The same transmitter with the same power won't reach someone 600 miles away on some days. It's all variables and how much the electromagnetic waves are absorbed.
 
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I have been looking around the web for a nice replacement green laser pointer, (if you have any cheap sites, link me up), I found this one..
green laser

Im looking at the 'handheld 300mW (FDA) 0.5 Kg 121.20 pound one.

Im confused on the spec sheet tho.., it says 'Range in darkness (m)
500-1000'

is that half a kilometer or the best part of a thousand miles ??!

surely it would be more than a kilometer in darkness, my 250mw cheap chinese one that looked nowhere as good as this did more than that!

A thousand miles, surely not...
I bought it, and I really recommend the 100mW version.
Mine is measured at 200mW. Expect a review of it on tuesday or wednesday.

Rallerboy
 




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