hi guys, i just got my 65mW 532nm from o-like today, and i played it for a whille and im pretty shocked how bright the light beam is, compared to my phr 100mW, it seems so weak, but even tho it burns things way faster than the greenie, but i really like it, and i was pointing to the sky at night, at the first i saw there were few air planes so i decided to play it later, then later i went out again i was "shooting" around whereever i could point at, the stars, trees.....etc anyways i just wanna know how far can my 65mW go, it seemed pretty far, and does anyone know how high is the aircraft, i meant the attitude maybe, i think is around 6-9 km!! please let me know thanks

kai

Think of it like this.

If your laser has 1 mrd it would get 1mm bigger for every meter it goes and when it leaves the laser it's 1mm.

So one km away it would be one meter wide.

So then take away the amount of power you'd lose from all the dust in the area and how big the dot is.

Then if the area of your eye that asorbs the light is 1cm and the dot is a meter wide and your laser is 100mw then 1km it would be 1mw to your eye or less.



Oh and lasers go forever .

That's the longest sentence in the world! congratulations!!

Commercial aircraft, the kind that carry many people from city to city, usually fly anywhere from 25,000 to 42,000 feet depending on airspace, traffic and desired route. Some private jets can fly up to 52,000 feet.

EF: There is a train station in Wales with a name almost as long as that sentence

Basically lasers go on forever, until every last wave of light has hit some tiny particle somewhere in space. Stars can be seen clearly several thousand light years away and their light is not even coherent, even if they ARE very very bright. My guesstimate would be that your laser could be picked up by extremely extremely responsive gear (which could measure every single photon) a couple of planets away.

Now Eku has answered pretty well about the visibility already. A laser is always brighter seen from the recipient's point of view, and if that person was standing in total darkness your 100mW would probably be visible about 5km away.
I think this part has been answered way better some other place on LPF and it is difficult to say what a "visible" laser is.. whether the mere fact that you can sense some change in light is enough or that you need to see a clear beam coming towards you for it to be "visible".

Anyway you should never ever shine at or near an aircraft, no matter how dim you think the laser is. You cannot estimate the hight of the plane well enough and cannot estimate how much light is visible at that distance. Pilot's eyes are also adjusted to very sensitive night vision with very dim control boards in the cockpit and so on, and a tiny flash from a laser might be enough to distract them and cause them to report your laser, or in the worst case cause an accident.
Also pilots often stray from their planned flight path (I should know, about 10 fly straight over my house every day even though their route is listed as 8 miles away!) and it is therefore even more difficult to estimate hight and location of planes. Just don't shine it at planes. Ever.

Another interesting thing observed by many here on the forum, including me, is that the longer the wavelength (eg. red 650nm), the further the beam seems to extend into the night sky, while shorter wavelengths seem to create a fatter and more visible beam close up, especially blu-ray 405nm which can appear as thick as a baseball bat at just 10 yards distance.
My theory on this is that it is caused by short wavelengths moving up and down more and therefore encountering more particles to light up, while long wavelengths move less and therefore do not encounter that many particles so the beam is still not weak at a distance.

how far it goes might be irrelevant. but a cool party "trick" is go out side on a cloudy night and shine it directly up and you will see it hit the clouds. with my 50mw ledshoppe pointer i can see it reflect on a high rise window at over a mile away.

to see it hit the cloud, first point it to open sky, the laser will seem infinite. Then sweep the beam to the clouds above you, and you will see a bright dot. that is where it hits the clouds

sorry man, because my english is not really good!

thanks for you replied, i think i got it, and yeah I will never shine it at airplanes or people, thats really dangerous!!

No apology necessary.. I was just messin' with you anyway.

That is actually a good question, not silly. You should create a thread in the Science & Lasers section I'm so proud of asking how far an XmRad laser can get while being visible for a human.

i have a 30mw dealextreme kaleidoscopic that goes 5 kilometers far!!!!!checked with google meter. the dot is very big at 5 km... and not very shining.. bt i saw it with the binocular...and it exists at 5 km..... goood......for a 30mw. i don't know how could be a true 200mw seted at a good divergence.... mmhmhhmhhhhhhh ( like homer simpson) sbav