A laser beam will continue infinitely, until it is stopped by something, because it is simply light. The divergence of a laser can tell us how the laser spreads, so the lower divergence that you have, the higher concentration of power per unit you will have for a longer amount of time.
But for the most part, from what I have experienced, if you shine a laser into the sky, it doesn't just suddenly "stop" somewhere in the universe. It's pretty much going to be a line forever. Therefore "range" for visual purposes is somewhat of a MOOT (corrected spelling) point. If you are working with something that requires a certain power per unit to be effective, however, range is definitely important, because at a certain point along the beam's propagating path, there will no longer be the required power per unit to accomplish the task you wish it to.
please read post 3.
please read post 3.
I have.
Hello,
How important are the mW for the beam trow of the laser ? With other words does higher mW guarantee longer beam range and concentrate spot ?
Which is the best "trower" under 50$ ?
Thanks !
What in God's name is a trower, and how does one trow?
To answer the OP's question though. If you want to see the spot at a very long distance, You want a laser with high power AND a low divergence. Longer wavelengths suffer less atmospheric attenuation, but at the distances being discussed, this is pretty moot. At distances where atmospheric attenuation becomes a strong factor, you wouldn't be able to see the dot yourself anymore anyway.
The power and the divergence are important. What about the "color" of the laser ? Red or green is preferable for long distance spot ?