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Thread: What about Scan-thru

  1. #1
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    Default What about Scan-thru

    I didn't see a spot in "lumia" for scan-thru glass/filters. So far, I have the obligatory diffraction grating, lenticular optics, a nice fresnel that produces great streaks, a 6 and 8 point star burst filter, and a very gentle convex lens (before scanners so, not technically a scan-thru). I am trying to find other materials that work well for scan-thru and was wondering what other people were using in their rigs. I know the Laserium and AVI style rigs have many different filters and would love to see a catalog of what they're using. Hoping DZ chimes in as his dual AVI has some good filters.

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    Laserium used all sorts of stuff over the years. One of the upgrades to the mark 6 were quick release scan glass (through) mounts to make changing between shows less than a complete pain in the ass. There were various diffraction effects of course.
    Fuzz glasses - just a clear piece of Plexiglas with a "dusting" of clear lacquer sprayed on it.
    Star filters - Plexiglas with horz and vert lines scored on one surface - takes some experimenting to keep the rays from going everywhere.
    Halo - just Plexiglas that's been rubbed with paper with a circular motion.
    There was a photographic filter that was a fresnel with the center clear - that was a nice effect
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

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    Would be nice to catalog this stuff and photo it for a history book before it’s all lost to time.

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    Laserium did some really good shows - for their time - but it's time to do better - I just haven't figured out how to build a success like Laserium in what passes for a planetarium today...
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  5. #5
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    They did do some amazing things. I saw about 15 Laserium shows back in the 80s and 90s. The one thing Laserium did vs every single modern show today is "screen" edges. There were none. Since I don't have an analog console at my disposal, I am very careful to avoid edges. Abstracts look great until they hit the edge of the "screen". Because of the lack of edges, Laserium always felt immersive. When the lights went out at Griffith, I was floating through space. In a word, it was awesome.

    Thanks for the info regarding the scan-thru. I was curious about the "dusted" plexi as I had tried different frosted glass, going as far as lighting sandblasting to get a diffuse beam but it was always too much and the scatter was unintelligible. I'll have to try the lacquer out. The cool thing about that is the ability to stencil a pattern of of lacquer. A lot of new things to try out.

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    A friend of mine said something along the lines of "the thing about fulldome" is there's "no frame". He's wrong, black is the frame. ( Well, gray in most planetariums in the US) I saw literally hundreds of Laserium shows by other laserists, and performed a couple thousand myself. Laserium is still special memory for me, but I look at what's done today...
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  7. #7
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    did someone say scan through?

    suppose you're thinkin' about a plate o' shrimp. Suddenly someone'll say, like, plate, or shrimp, or plate o' shrimp out of the blue, no explanation. No point in lookin' for one, either. It's all part of a cosmic unconciousness.

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    Has anyone been able to use galvo slow enough to scan over a lumia piece in place of a rph motor? You could play with dots of color in different by close spaced places on the lumia. And also make linear rather than radial movements. Even reverse. Try a slow beam show.

    Swami you should call that show mushrooms in a cave

    That’s like beam brushing. The color ring looks like fire

  9. #9
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    Quote Originally Posted by kecked View Post
    Has anyone been able to use galvo slow enough to scan over a lumia piece in place of a rph motor?
    With Pangolin, I can get the abstract oscillators to scan sine/cosine at .01hz so.... yeah, pretty damn slow!

  10. #10
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    Quote Originally Posted by kecked View Post
    Has anyone been able to use galvo slow enough to scan over a lumia piece in place of a rph motor? You could play with dots of color in different by close spaced places on the lumia. And also make linear rather than radial movements. Even reverse. Try a slow beam show.
    Yeah, I do this all the time as I have 1.5 projectors that can't rotate a lumia effect. I never tried to see how slow I could make it go, but I'd probably want to ensure that I was using a DAC with 16 bit resolution to ensure the finest/slowest possible movement in a tightly confined space. (Hitting lumia at a significantly obtuse or acute angle would often throw the effect way off center.)

    Galvos with error correction / integration might help to produce the smoothest movement as well. In any case, having the galvos do the work allows you to virtually put beams of different color on top of one another, very close to each other, or far apart . . Not to mention shapes and their associated movement. I've got several examples, but I need to spend some time filming them . . after the 8 other projects I've got in process!


    Laserist: Thank you for sharing that information regarding lumia effects used in Laserium. The light dusting and halo effects are simple things that others can easily reproduce.

    -David
    "Help, help, I'm being repressed!"

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