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Distance Experiments

hurplegrappers

hurplegrappers

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:lasergun:
Distance Experiments

hi all, this might already be covered somewhere else on the forum i'm sure someone must of thought of this before, if so my apologies (suppose links will follow) but I was just wondering if any of you have some links to video clips where; from a high altitude fixed position someone blasts a laser across the night sky and someone else travels to it's furthest point to get an approximate (or as accurate as possible) REAL distance that these various high powered beauties can achieve? i've tried looking for similar type videos on youtube but couldn't find any.

if not maybe we could use this thread to kick off such experiments? I suppose apart from the obvious requirement, a nice dark sky, one or 2 devices to capture the video, a willing friend/s and a full tank of petrol lol :yh:

my laser is on order so i will have to wait until it's received before posting my contribution but if any of you guys are up for the challenge it would be interesting to see the results....

hurps
 





Dusty

Dusty

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Interesting topic, I have wondered about this before...I have recently received a 200 mW green from rayfoss, and I am still waiting for a DX true 50 mW green and a custom built 8x blu-ray approx 350-400 mW (to be decided later), so I would be up for taking part in any experiments and/or contributing to this thread. I notice that you live in Wales, which part?
 
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ElektroFreak

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hurplegrappers said:
:lasergun:
Distance Experiments

hi all, this might already be covered somewhere else on the forum i'm sure someone must of thought of this before, if so my apologies (suppose links will follow) but I was just wondering if any of you have some links to video clips where; from a high altitude fixed position someone blasts a laser across the night sky and someone else travels to it's furthest point to get an approximate (or as accurate as possible) REAL distance that these various high powered beauties can achieve? i've tried looking for similar type videos on youtube but couldn't find any.

if not maybe we could use this thread to kick off such experiments? I suppose apart from the obvious requirement, a nice dark sky, one or 2 devices to capture the video, a willing friend/s and a full tank of petrol lol :yh:

my laser is on order so i will have to wait until it's received before posting my contribution but if any of you guys are up for the challenge it would be interesting to see the results....

hurps
Click to expand...


Light travels an infinite distance with no attenuation in a vacuum. This means that the only limiting factors are impurities in the atmosphere and spreading of energy due to the divergence of the beam (divergence is not the same as attenuation. Divergence means the photons spread apart as they travel, meaning less of them will reach a target sensor as they will have expanded to an area larger than the receiving sensor area). Photons from a 5mW laser source can be detected at extremely large distances from the source with sensitive enough equipment. If photons from the laser source reach the vacuum of space they have the potential to travel infinitely far from the source if traveling a pure vacuum and given enough time.

Suffice it to say, photons can easily travel massive distances.
 
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hurplegrappers

hurplegrappers

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Dusty said:
Interesting topic, I have wondered about this before...I have recently received a 200 mW green from rayfoss, and I am still waiting for a DX true 50 mW green and a custom built 8x blu-ray approx 350-400 mW (to be decided later), so I would be up for taking part in any experiments and/or contributing to this thread. I notice that you live in Wales, which part?
Click to expand...

nice1 dusty good to hear you're up for having a go, btw i live in a small village the nearest town being pontypridd (where tom jones is from hehehe) the village i live in is in the grip of x-factor fever at the moment because it's the same place young lloyd daniels is from lol bless he's only 16.

Elgranto7 said:
Some videos of distance shots..
But nothing to find the end point at which the laser is visible.

i wonder if a handheld could go across the english channel :thinking:
Click to expand...

lol @ english channel.. you'll need more than a tank of petrol for that one dude, funny.. thanks for the links but you're right, none have filmed the point where the laser fades away (or as close to it as possible)... maybe that's where we can make this experiment different, more emphasis on finding the end of the beam or point of serious fade.
 
hurplegrappers

hurplegrappers

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ElektroFreak said:
Light travels an infinite distance with no attenuation in a vacuum. This means that the only limiting factors are impurities in the atmosphere and spreading of energy due to the divergence of the beam.
Click to expand...

yeah man suppose your right, atmos & light (i.e moon, fog, drizzle etc) conditions would play a huge roll.. taking this into account is it really worth doing then? sorry i dunno coz i'm new to all this and you sure sound like you know what you're talking about. i suppose posting the general light & atmos conditions in the findings/results would give us a better idea though. maybe also camera/video capture device used?
 
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mfo

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Get two hot air balloons and let one shine a laser at another.
 
Gsquared18

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What about a test to see how far "the beam" can be seen? I live in the Smoky Mountains so the air quality is always good for night lasing. I got a Led Shoppe 50mW coming so I will try to record a test on how far the beam (not the dot) can be seen. i shot the Optotronics 50mW down my neighborhood's main street which is over 100 yards long and my neighbor easily saw the beam about 20 feet in front of him. He said it continued into the forest (another 20 yards) until the dot was hitting trees. He also said the dot was smaller than golf ball size and even though it was hitting the bark on the trees which absorbs some of the light, it was just too bright to look at.
 
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Murudai

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Me and laze_doctor did an experiment like this. I went to the top of a large hill and shined my RPL-300 down at a wide road about 2km away. He went down to the road and observed the dot, it was about 1m wide I think.

I never saw the dot, so you'd need to ask laze_doctor what it looked like, lol. Apparently the beam was insanely visible.
 
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Using a telescope as a beam expander will help you to get the laser over 10 or miles easily even it's 200mW
 
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ElektroFreak

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Beam visibility is dependent on airborne particles (called aerosols) that reflect the light and make the beam visible. The aerosol layer ends less than 5000 ft above us. Therefore, a visible laser beam directed straight upward can only be seen to extend about that far before it abruptly ends. A 20 mile visible beam can therefore only exist if the laser is projected almost perfectly horizontally.
 
Rob

Rob

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This has been something I've been wanting to test myself but never had the time or the right area in which to do it. Someday soon I hope I can though.
 
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