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FrozenGate by Avery

35 mile laser shoot

steve001 said:
That's darn close to what I said. With typical beams diameters of hand held lasers a beam diameter of 10mm is close to what you'll have using a 10x expander. And a reduction of divergence about 0.12 mrd. That will put more light into a given area when compared to a 3 or 2x expander.

Using commonly available lenses with focal lengths of -6mm and 60 for a 10x expander and
-6mm and 18 for a 3x expander one can see that the Rayleigh length (RL) is greater with the 10x expander.
10x expander
0.12 mrd
RL 83337.648 mm or 273.41748 feet
10mm exit beam dia

3x expander
0.40mrd
RL 7500.348 mm or 24.607441 feet
3mm Exit beam dia.
So what this means is this. The RL is the length over which the beam will expand the square root of 2 or 1.4 times it's initial diameter. After that distance the beam expands in a linear fashion. The 10 x expander will out perform a 3x expander once past the rayleigh length of the 3x expander
Click to expand...

I see what you're saying here. Thanks for laying it out in mathematical terms..
 





Lol u think 10x is cool.... I have the 30x Beam expander for my Rpl 450 and man it is a 30cm dot for almost ever : ) my rpl had a .8mrad to being with so i ended up with .026 mrad divergence : )

lol how u liking your rpl?
 
ElektroFreak said:
I see what you're saying here. Thanks for laying it out in mathematical terms..
Click to expand...

Here's something more if you include another -6 focal length lens in your beam expander so that your expander resembles this )])] [) you'll have . Rayleigh Length
a 20x expander
beam diameter 2cm or 0.78 inches
Rayleigh Length of 333337.651 or 1093.62 feet
A divergence of 0.06mrd

Placing some space say 0.5cm between the two -6 lenses will
will increase the RL to 361694.876mm or 1186.662979
while only marginally increasing beam diameter from 20cm to 20.833 cm or 0.82 inches
The reason you'd do this is to keep the expander's dimensions as short as possible but perform like a two lens Keplerian system using a longer focal length positive lens.
 
Last edited:
a well deserved :bumpit:

holy crap that was an amazing read... although I must admit that it did get a little beyond my understanding at times

I live in a mountainous, minimally light-polluted town near LA that would be pretty great for testing, however I don't know too many laser enthusiasts around there (okay, none.)

I'd be more than happy to test something like this, though!

peace & thanks
-cmak
 
cmak said:
I live in a mountainous, minimally light-polluted town near LA that would be pretty great for testing, however I don't know too many laser enthusiasts around there (okay, none.)
-cmak
Click to expand...
[OFF TOPIC]
Hey - u know... i live in sunny Natal, the south america's closest spot to africa (check world map) and although i don't live in a city in the mountains i do feel like you sometimes...
but i gotta tell u... :eg: hehehe your statement, as quoted above, does really sound like unabomber!
[/OFF TOPIC]

but there is also another point:
so correct -me if i am right:
it means to get sparse photons as reflection from the moon surface (to see a dot in moon surface) i would need a "pen-pointer" around 5GW?
humm....

[OFF TOPIC- Rematch!!]
wow! if Dr. Brown had DPSS diodes, he could be writing his name on the moon with the help of lightining strikes, instead of building cursed useless timemachines :na:
[/OFF TOPIC- Rematch!]
 
pardon my asking, but what about my post had anything to do with Theodore Kaczynski?

peace & thanks
-cmak
 
@-cmak

hehehe. it was just a joke. pls don't be upset ok?
the thing is: u said u were living in the mountains, in a small-not-full-of-lights city... using high tecnology, potentialy hazardous equipment: it sounded like the unabomber, i bit like him... so it reminded me - no offenses intended!
btw -gee i'm so offtopic today... -
did you notice that this guy still lives!? wow! i thought that he was dead!

Ok!
/Offtopic! i'm affraid one of the moderators would hear my posts reported! from now on i'll stick it to the topic... :thinking:
 
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