How far can it travel

Sorry if this has been answered before but how far can the dot stay in significant small size by using a 445 nm diode and a 445 glass lens? a km or 2,? :shhh: Thanks

what would you consider small? Under a foot wide?

AUTO XX said:

what would you consider small? Under a foot wide?

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Yea sorry I should have defined that. Well lets say under a meter.

I'd have to say about a km for the ones I have done.
focused to infinity the beam profile is pretty bad ^_^
at ~150 yards the spot is ~4"
I'd be interested in the 405nm beam profile though, still waiting on parts for the one I am building.

There is a tower almost exactly 2km from my house. My ~700mW WL S3 Arctic could easily project a dot onto the tower given an avarage night. It was probably a human sized dot/oval, but at night it was visible. In the daytime, I'll bet you have a tough time seeing a typical 445 dot past 0.5km.

An aixiz lens can get the beam down to ~1.35mrad and I think I've seen talk of <1mrad with some of DrLava's correction optics. Around 1mrad ain't too bad at all even if the beam is a rectangle. Optimally, you're looking at about 1m (39" long) bar at one km. that should be fairly visible especially at night. Low Clouds are about 1.5km above sea level and most other high clouds are between 1.5km-7km above sea level.

For reference, on a clear night I can see my 5mW greenie pointing at trees at least just about 1 km away. Although green is VERY visible at night and the green pointer has ridiculous divergence. The beam (in the dark or smoke) looks like a needle piercing the air.

From 1/4 Mile distance.

With a starting beam diameter of 3.5mm for the fast axis, the Bar was about 1.422 meters long(I forgot to measure the slow axis)

Good beamshot's were not possible since my monopod was not good enough to do a long exposure shot(I only have 1 tripod)

I also used my WL PD Pro 100mW 532nm. From the same distance the dot was 0.610 meters across.