Touching the sky

[Coby]

Yesterday I pointed the 100mW green to the sky and I saw a clear dot in the clouds.
The weather was a little foggy and the clouds were low and massive.

Ok nice to hear! I guess this week is a lot better to check this as the weather is worse now

 

[weeba2kv]

@ElektroFreak Yes but i don't really count that as hitting the "sky" as the title sais hehe , i would say WOW with clear sky and high clowds and then with a good powerlaser hitting clowds atleast 2000 meters high or more

 

[Wos]

I can confirm that you dont need to much power to touch the clouds. My 145mW, (actually was about 85mW) did it. Not very often, but it wasnt like very rare either. With the right weather conditions I think its pretty "easy".

I would love to share a photo with you but i did the stupid thing called potmod and...... R.I.P to that greenie.

 

[2100]

Your eyes can't focus for nuts with 445nm, and definitely not 405nm.

But if you use a pair of binos, i am sure you'd be able to spot that 445nm 2W. Even with a pair of 7 x 25mm which probably gives you the same exit pupil (not much additional light gathering than your eyes, but it blows up the image so it's easier to see). With a telescope it's even easier.

The O-like 100mW with beam expander is great. Decent power at 0.3mRad only (could be better), from what i measured.

I shall try to measure the lux of it one of these days at 45m, during 8am or something. (it attracts too much attention at night). The beam should still overpower the amount of ambient light. The lux meter is ok for 532nm (but not 445 or 405nm)

 

[brendon7358]

I used to be able to see the dot in the clouds (regular cumulus the kind you point out shapes in or overcast skies) at dawn (just when the sun goes down but still bright enough to see) with my 200mW 532nm. I can also see it with my 1.2W 445nm at night but only if I focus it very well to infinity.

 

[cheech226]

A beam expander narrows/tightens the beam? It should be called a beam narrower or beam focuser then!

first, the beam is expanded from it's original diameter by the power factor of the expander, a 10x expander will take a 1mm beam and make it 10mm. altho at first this seems a "loss" we are also reducing divergence by a factor of 10 which of course is a Big plus. go figure - you'll see

 

[ShortyInCanada]

So the real limiting factor isn't so much the beam as it is the ability to perceive the "spot" in the sky.(on the bottom layer of clouds.)
Something not visible with the naked eye may be seen with binoculars.
If not with binoculars then with a low power (and cheap) telescope.
The dot is there all the same, but the ability for you to see it becomes the problem. How many photons of the reflected light will be able to make it back to your eye ? And with the source being so close to you will it interfere with your ability to see the reflected light as you have to overcome the brightest part of the beam to see the dimmest reflection ? It would seem that the farther you are away from the source the better your chance of seeing the reflection on the clouds.
Could make for a pretty informative science experiment.