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Thread: Beam size issues RGB

  1. #21
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    Well I think i've figured it out. I was looking at the beam with no fog/smoke real close (1 inch) and it's kinda like looking at your tv screen @ 1", you can see each individual RGB 'pixel'. Far off though they all blend together mixing like 1 color. I was just kind of disappointed that on a semi-clear night the beam wasn't more of a yellow or orange -it was kind of a dim gray color. I guess that's normal. I'll have to wait for a foggy night--stupid question tho i guess oh well, back to work :/

    I would like to figure out how to mix colors using fiber unless too complicated/ expensive.. probably have to deal with numerical aperature numbers and calculations -things I know nothing about

  2. #22
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    buy a fog machine!
    Now proudly stocking and offering the best deals on laser-wave

    www.lasershowparts.com
    http://stores.ebay.com.au/Lasershow-Parts

  3. #23
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    I'm mainly into outdoor beam-shows! BIG fog machine..

  4. #24
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    Cool

    Sorry for my late reply (been busy as hell at work), but it seems that you've already discovered the solution. (fog)

    Yeah, really close to the scanners I can sometimes see a HINT of the green and red speckle that you refer too (though never as distinct as your rendering above), but most of the time it's foggy (or dusty) enough in my house that I get the yellow beam to show up even before the light leaves the optical table. Of course, I rarely have the lasers on without also having a fog machine running. (Then too, I have two cats and two kids, so the house isn't exactly up to clean-room standards!)

    As to your other commend about being mostly interested in outdoor beam shows, I'd caution you to always keep this in mind: If you want to do outdoor shows, you need one of two things - either a *huge* freakin' fog machine, or a *huge* freakin' laser! If you don't have fog, you need power, and lots of it. Sorry, but that's the nature of the beast.

    While I love the red beam from my Maxyz module, there's no way I'd attempt an outdoor show with it. (Or even with a pair of them...) You need several watts of red, and at least a watt each of green *and* blue, to even think about an outdoor show. (And truthfully even 5 watts of whitelight can look lame when you're outside with no fog - especially if there is any other light in the area.) Most of the guys I know that do outdoor shows start at 20 watts and go up from there. And damn few of them try to pull off an outdoor whitelight beamshow. Mostly they save the whitelights for graphics, and just use a big argon (or even a DPSS green) to do beams.

    On the other hand, if you can control the outdoor venue somewhat (fences, walls, trees, to keep the wind down), there are some large fog machines available that will work even with a modest breeze blowing. You just need to place them strategically to use the wind to your advantage. Big air movers (ducted fans) can also help some. Not exactly a cheap solution, since large fog machines are expensive and you'll still need several of them, but it will probably be cheaper to go that route vs buying and operating a 20 watt laser...

    Adam

  5. #25
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    do outdoor shows start at 20 watts and go up from there
    Now you sound like the guys at .alt- "Go big or go home"
    Actually, surprisingly a 30 mw argon 488nm thru a foggy night and lots of fireworks smoke ( a Jul 4 party) was bright enough (outdoors) to ger a few ooohs and ahhhs, (it was probably for the fireworks) so I'm thinking it's more of a visual perception thing epecially with a nice color like 488. Maybe rods and cones and nite-time perception or sumpin?

  6. #26
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    Hi Steve-o

    Well, doing a backyard laser show for your neighbors is something different. After all, if the lasers don't look great - who cares? It's not like you're charging admission or anything, so the people probably won't bitch about it if the lasers look lame.

    Then too, if you really control the crowd... Keep them within a 10 degree arc immediately downrange of the projector, for example... You might be able to get some effects to work.

    I, too, like to set off fireworks (the powerballs video in my gallery is ample proof of my pyromania), and I've always wanted to combine lasers with fireworks. But the few experiments I've done in my backyard have taught me a lesson. Namely, I don't have enough power. Not with 40 mw of 488nm blue. Or with 100 mw of 532nm green. Or even with 200 mw of red, 75 mw of green, and 40 mw of blue from my whitelight rig.

    I can just barely pull off a graphics show in my yard, but even then the streetlights are a problem. As for beamshows - well, they just don't work in my yard. My two fog machines aren't enough to fill my yard with fog (even with no wind), and you can't always rely on the smoke from the fireworks to provide the rest.

    I'm not a perfectionist, but I do like my laser shows to be "memorable", in that they're powerful enough that people say "wow! I've never seen anything like that before!" And I just can't get that reaction with an outdoor show - at least not with my current equipment.

    Now, having said that, I know exactly what you mean about some of the guys on alt.lasers. I've heard the "go big or go home" line before, and yeah - it bugs me when they say it. But I understand that they do have a point. In the commerical business, there are a lot of yahoo's out there trying to pass off a 1 watt projector as "outdoor capable". When the show turns out lame, all the producer learns is that "laser shows are lame". So the next time, when a really good laser company comes along and promises to light up the world with 20-30 watts of power, the producer says "go to hell", because he's already seen it and it sucked. But of course, what he saw was some cheezy aproximation of a real show.

    While I can understand why the "big guys" in the industry are pissed off about this development, I still can't condone their condescending attitude towards the hobbyist community. (This is why I don't spend much time on alt.lasers anymore.) If they could find a way to get their message across without sounding like a bunch of dicks, maybe they could stop people from bidding on larger outdoor shows until they have the equipment they need to do it right.

    I will say that in a *completely* dark room with lots of fog, just about anything looks great. (Even 14 mw of red from a hene, and just 8 mw from a green pointer!) So again, if you can control the venue, maybe you can create some cool effects. But I haven't bothered to try it outside beyond the few experiments I've attempted. I get much better results inside. (Plus it's not nearly as hot inside as it is outside!)

    Adam

    Edited to fix link. Need to click on the movie camera icon to play video.
    Last edited by buffo; 06-11-2007 at 07:23.

  7. #27
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    OHHH i see. The nearest streetlight from our house is 25 miles away. We live wayyy out in the sticks. Telescope viewing is also good from Floyd, Va. Darker is probably better, then, for outdoor shows.
    Re: .alt
    Yeah they can come across as assholes. I visit there if I cant find an answer here, which is rare.

    I couldn't see your vid from here at work- I'll have to wait till Thu when the DSL is finally connected at the house
    Last edited by steve-o; 06-11-2007 at 07:19.

  8. #28
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    Steve-o

    I just realized that the original link to the powerballs video was broken. Try it now. (You still need to click on the movie camera icon to play it.) It's hosted here in the PhotonLexicon gallery, so you should be able to view it at work. (Well, assuming you can view a movie in Windows Media Player, that is...) Do they have the desktops locked down that tight?

    RE: living in the sticks. Yeah, that would help some. I actually live in a fairly dark subdivision. Street lights are spaced out about one every 10 houses or so. (!) But then you've got lights from the house to contend with, plus passing cars, etc. But I can see how living in the country would help.

    And yeah, darker is *always* better when it comes to a venue for a laser show. I used to live in the country back when I lived in Wisconsin... That would have been a good place to try an outdoor show. But there's no way I could have afforded it back then. (Sigh.)

    Adam

  9. #29
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    Hi Steve-o;

    The "powerballs" are actually 1 inch mortar shells. You know, the one's that look like mushrooms with about 9 inches of green candy fuse on them... You're supposed to drop them into a launch tube before lighting them. The first "pop" that you hear (and see) in the video is actually the lifting charge going off. If I had put it in a launch tube, the pop you hear would have sounded a bit louder (more like a thooomp!) as the lifting charge explosion propelled the shell roughly 100 feet into the air. The delay between the two explosions is caused by the remnants of the fuse burning through the shell to the very center, where it sets off the burst charge.

    The burst charge is the *big* bang you hear. Normally a mortar shell isn't nearly this loud, because the burst charge only needs to be large enough to ignite the stars in the head and dispurse them in a symetrical pattern.

    But in the case of these shells, there isn't anything inside the head except a whole bunch of powder for the burst charge. So that's why they're so freakin' loud. (Nothing but bang!) In fact, I strongly suspect that these little babies are actually in violation of the spirit, if not the letter of the law regarding class C fireworks. I have no doubt that if you held one of these in your hand it would amputate it at the wrist when it went off. They remind me a lot of the original M-80's from the 1970's. That's a lot of explosive power for a class C firework. But they were purchased legally at a reputable store, so I figure I'm in the clear. (On the other hand, I've never seen them anywhere else, and the store I originally bought them from has been unable to get any more of these things despite the fact that it's been nearly a year since I bought them...)

    I've still got 1 box of twenty left. I'll probably shoot most of them this 4th of July, but if I get the green light from our host for SELEM, I might save a couple to bring along...

    Adam

  10. #30
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    Sorry Adam I was deleting to add and then your reply popped up
    oh well--

    Prev. post:
    Adam-
    I remember that video- F'ckin AWESOME!!
    I too am a pyro-fan.. Done some wild shit in my time
    What is the first mini-exlosion B4 the BIG BANG??
    That was cool!!

    I used to do the pyrotechnics for the band I was in. There was this stuff called concussion powder that came in 2 parts. You'd mix them together, put the powder in a heavy open-topped thing ( I used the ends off of the bass players bar-bells- he didnt use them anymore) and ignite it with a punk. (well i used a small piece of a stranded wire that blew when 120VAC was put on it and )---BOOM!
    Ahhh.. the good ole days..

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