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can reach 70 miles with this laser?






The first one, the power is better and the divergence is slightly lower.

But I doubt you can even see 70miles, since the horizon at sea level is only 3 miles away... You would have to gain ALOT of height to see 70 miles.
 
The distance thing is a little hazy in terms of just how far the laser will go. If you're asking if you can see the laser's dot on a mountain 70 miles away, not likely. If you're asking if the photons from you laser will travel 70 miles, the photons from any laser will travel indefinitely unless blocked by an outside force.. Light travels an infinite distance in a vacuum, so the only things that will stop the photons from your laser from traveling on forever are solid opaque/translucent objects and airborne impurities. The photons that reach space will continue traveling forever unless they are blocked by an object or objects.
 
And not only what Elektro said, but at 60 feet altitude the horizon is 50 miles away :)
 
slammer99uk said:
And not only what Elektro said, but at 60 feet altitude the horizon is 50 miles away :)
Click to expand...

It would be 9.5 miles away with a 60 feet altitude :)

You would need to be 3260ft in the air to be able to reach 70 miles, as long as nothing is blocking the beam.
 
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That's assuming a perfect spherical surface, right? Given the earths imperfections it seems like it would be highly variable all around.
 
so if you shined it while space walking during a shuttle mission, yes you can project your laser 70+ miles, other than that, it's pure fantasy.
 
Asherz said:
It would be 9.5 miles away with a 60 feet altitude :)

You would need to be 3260ft in the air to be able to reach 70 miles, as long as nothing is blocking the beam.
Click to expand...

My mistake, for some reason I had those figures stuck in my head filed under "useless facts to remember" :)
 
hey guys the famed DL 10X beam expander is "out of stock" on their site, and I haven't yet been able to find where else it is for sale. I figured it was probably manufactured by CNI like most of the other DL products, but the only ones they offer look totally different and I have yet to find a good review/info on it. What would you guys recommend? I'm open to both a standalone one that you just shine any laser through as well as one that attaches to specific models via an adapter (the way the DL one does).

oh and thanks for the link, Constantino. It was a great thread and an amazing read

peace & thanks
-cmak
 
cmak said:
hey guys the famed DL 10X beam expander is "out of stock" on their site, and I haven't yet been able to find where else it is for sale. I figured it was probably manufactured by CNI like most of the other DL products, but the only ones they offer look totally different and I have yet to find a good review/info on it. What would you guys recommend? I'm open to both a standalone one that you just shine any laser through as well as one that attaches to specific models via an adapter (the way the DL one does).

oh and thanks for the link, Constantino. It was a great thread and an amazing read

peace & thanks
-cmak
Click to expand...

I have that beam expander but have never been able to notice much difference in terms of spot visibility at a distance. Part of the problem is working out the correct focus position on the focusing ring to get the least divergence. I used it in the Alps a few days ago and couldn't honestly see any real difference with and without. Still, I guess the physics doesn't lie ....
 
raphael said:
www.rayfoss.com /productn.asp?ArticleID=65

or

www.rayfoss.com /productn.asp?ArticleID=55
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Depends what you mean. I doubt any handheld spot would be visible to the naked eye at 70 miles. Assuming 1 mrad divergence, the spot would be well over 300 feet across. Almost certainly too dim to be seen. I have some fairly powerful handhelds, but I've never been able to detect a spot on a solid surface from more than about a mile away.

On the other hand, if you are talking about looking into the beam, then the limit is ~ ten thousand miles, though of course then you'd need to be far out in space to see it ;-)
 
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