Long range laser projection?

[norty303]

I'm after some real world experiences of long range laser projection please?

I've been asked to look at whether it might be possible to get a logo onto the side of a mountain, and at the location there are 3 possible targets (sheer flat faces of rock on the mountain), ranging between 900m to 1.2km from the location where the projector would need to be sited.

Power at the location is limited so solid state is going to be the way we're going to have to go if its doable, and the transport options aren't going to stretch to getting a 'scope there either (its across sea and country by road in a van full of PA gear and staging already).

They originally asked for a red logo but I can't realistically see how we'd do that simply and in a reasonable budget, so I've simplified the problem down to 'could we get a logo of any colour onto the mountain'.

I reckon we could get an 8W 532 OPSL there inside the budget, but would that cut it? Certainly the beam specs would be in our favour.

Anyone done this, or even better got any pics of similar stuff to look at so i can get a sense of what might be achievable?

[neutrino]

I remember doing something like this many years ago for a job in Nigeria with LM Productions. If I recall we were using a 5W Laser Quantum 532nm as the source. Let me see if I can find some photos. Distance may have been a little further than your target too.

[norty303]

That would be awesome, thanks.

[sbk]

I done long range projections but "only" 400-500 meters, you can see a picture there : http://www.sbk-laser.ch/sbk/index.ph...ry3.jpg&title=

It was with two 4W projectors, Viasho lasers with low divergence (0.7 mrad). Don't be fooled by the amazingly bright look of the projection, it's a long exposure shot but real result was still very good.

I did the same job again next year but with a single projector containing an OPSL 8W and it looked similar, only a tad better. Since I was expecting more from an OPSL, it seems that two projectors sharing the display are working better than one bigger drawing the whole image. I would say for a 900-1200m projection you need minimum 2x 8-10W OPSL fitted with very low divergence collimators...

[neutrino]

Sorry, can't seem to find photos of that part of the event. I have photos from everything else - typical! I know the year was 2003 but that certainly doesn't help.

[mixedgas]

One other thing. Consider Having good analog pots for X-Y image size and a VERY stable platform to scan from.
At long throws the software adjustments can be very course steps. Actually worth testing the size and offset adjustments long before your in the field.

Steve

[norty303]

Thanks for looking Neutrino. Might contact Stephen at LM, they're just up the road and we have emailed previously.

The logo is likely to be very simple, so I don't think it'll require 2 projectors. There wouldn't be a budget for it anyway.

Steve, already thinking about platform and stability

[neutrino]

Hope the project goes well. Looking forward to hearing the outcome.

If you contact Stephen can you say Rich Astley says hi. I haven't spoken with him for quiet some time now.

Cheers
Rich

[planters]

I think you can do this. I ran a big version of one of the standard RGB projectors with 20W to a mixed surface at about one mile. It wasn't impressive, knock your socks off bright, but it was visible. The surface was mixed scrub and rock, so a bit of grey and mostly greens at about a 45 degree to the vertical. The environment was dark especially at the mountain. From a distance equal to the throw (we were near the projector) the divergence isn't at all a problem because even a spread to a meter across at that distance is at or near the resolution of the eye. I would be more concerned if the viewer was much closer than the projector or if there was little bare rock. The trees ate it up pretty badly. I also thought at that time that we could easily improve the visibility by using 3-4 projectors with the same graphic, overlapped, to build up the brightness of the image.

[Laser Wizardry]

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