Wow! How is this done??

[White-Light]

Sorry if I'm being thick here but couldn't you use a large prism and attach it to the spindle of a stepper motor so that it sat alongside the laser and the beam shone through the sides of it as it rotated rather like the current lumina wheels, rather than having to build / buy a complex hollow spindle motor and shine it through the centre or is there a problem with getting large size prisms? If clearance was a problem I'd have though with a large enough prism you could have machined the corners off to make it round like a lumina wheel without affecting the performance of the core.

[depo]

Correct me if i'am wrong but.

That wouldn't give the same effect as a hollow bearing motor. Because the scanned image is not scanning through the center axis. This is what give it some kind of uniformity. As in the image is not being pulled towards which ever section of the wheel your scanning through which is the case in lumia wheels.

[laserist]

So... which one do I want to buy to experiment??

http://www.edmundoptics.com/products...productid=2034

What is the difference between aluminum coated, uncoated and VIS O coated? I'm thinking something in the 20 - 25mm range is right? Maybe 15 in a pinch although that seems kinda small.

Want it... need it...gotta have it!!

Either the coated or uncoated (not aluminized) would work for what I think is being talked about here. But I don't think the imagery in the video referenced in the original post had anything to do with a rotating dove prism. I'm not saying a rotating dove wouldn't do something interesting. That said if the prism is the last thing in the optical path it will severely limit the field angle of any effects you produce. I have toyed with the idea of using a dove to rotate beams feeding lumia effects, but there are other techniques that I would think have more promise.

The aluminum coated doves are for displaced retro reflection (the light goes in from what would have been the hypotenuse (a dove is a right angled prism where the corner opposite the hypotenuse is ground down parallel to the hypotenuse until you reach the range of total internal reflection looking through the diagonals parallel to what was the hypotenuse.) and reflects off the aluminized diagonal through the prism to the other aluminized diagonal and back out the toward the source but offset by the length of the path inside the prism. This is not the on you want.

Brian

[Bradfo69]

Either the coated or uncoated (not aluminized) would work for what I think is being talked about here. But I don't think the imagery in the video referenced in the original post had anything to do with a rotating dove prism. I'm not saying a rotating dove wouldn't do something interesting. That said if the prism is the last thing in the optical path it will severely limit the field angle of any effects you produce. I have toyed with the idea of using a dove to rotate beams feeding lumia effects, but there are other techniques that I would think have more promise.

The aluminum coated doves are for displaced retro reflection (the light goes in from what would have been the hypotenuse (a dove is a right angled prism where the corner opposite the hypotenuse is ground down parallel to the hypotenuse until you reach the range of total internal reflection looking through the diagonals parallel to what was the hypotenuse.) and reflects off the aluminized diagonal through the prism to the other aluminized diagonal and back out the toward the source but offset by the length of the path inside the prism. This is not the on you want.

Brian

Yes, that's my understanding as well. I think an aluminized one would be used essentially to let a prism make the beam do a U turn.

[Bradfo69]

I expect there will be a great deal of experimentation to try and duplicate some of the effects. I'm most interested in the "wreath" looking effect with a series of squares where the colors are rotating around the wreath in the "Tubular Bells" video (0:53) as well as the "Figure 8" patterns. (Of course, I could always buy their projector! But, I suspect it's a kings ransom. Besides, might come up with something more interesting in the process.)

[Earthnik]

Brian~

The discussion about the prism assembly is not meant to explain how the effects are done in the videos in question. Those effects already have been explained here ... two scan heads, conventional frames that have symmetry projected through light lumia and what I'll call soft focus, diffusion filters as well as various diffraction gratings. I have a grating from Peter Meyer which was always my favorite, a soft starburst that emulates most of what you see in the video. Pretty simple really. The prism reference was meant to broaden the discussion around creating a truer kaleidoscope with even more fascinating imagery.

Anything that enters, exits. That is to say that, if the distance between the scanners and the first prism surface is proportionately short enough to allow the entire scanned image in, then it will al exit with the same excursion angle, thus not limiting any "field of view" as you put it. But this does require a prism with a sufficient initial window.

I understand you may have never seen the effect and so your skepticism is warranted. You're simply going to have to take my word for it (as I don't know anyone with this type of assembly in order to prove my point), this is as good as it gets ... unequivocally the most psychedelic laser projection I have ever seen.

AND ... if you have other methods in mind that have more promise, please share them with us.

~Frank

But I don't think the imagery in the video referenced in the original post had anything to do with a rotating dove prism. I'm not saying a rotating dove wouldn't do something interesting. That said if the prism is the last thing in the optical path it will severely limit the field angle of any effects you produce. I have toyed with the idea of using a dove to rotate beams feeding lumia effects, but there are other techniques that I would think have more promise.


Brian

[mixedgas]

Brian,

I know there are other symmetry effects there besides the Dove, thats just the one I'm willing to talk about.

Steve

[Earthnik]

Steve ... the others trade secrets? *wink*

[laserist]

Brian~

The discussion about the prism assembly is not meant to explain how the effects are done in the videos in question. Those effects already have been explained here ... two scan heads, conventional frames that have symmetry projected through light lumia and what I'll call soft focus, diffusion filters as well as various diffraction gratings. I have a grating from Peter Meyer which was always my favorite, a soft starburst that emulates most of what you see in the video. Pretty simple really. The prism reference was meant to broaden the discussion around creating a truer kaleidoscope with even more fascinating imagery.

Anything that enters, exits. That is to say that, if the distance between the scanners and the first prism surface is proportionately short enough to allow the entire scanned image in, then it will al exit with the same excursion angle, thus not limiting any "field of view" as you put it. But this does require a prism with a sufficient initial window.

I understand you may have never seen the effect and so your skepticism is warranted. You're simply going to have to take my word for it (as I don't know anyone with this type of assembly in order to prove my point), this is as good as it gets ... unequivocally the most psychedelic laser projection I have ever seen.

AND ... if you have other methods in mind that have more promise, please share them with us.

~Frank

We use dove prisms for image rotation in Panoramic telescopes - with my eye almost against the base of one of our doves the field of view is about 20 degrees. With a right angle prism the field of view is 30 degrees to the reflection cutoff. There's no way that " ...if the distance between the scanners and the first prism surface is proportionately short enough to allow the entire scanned image in, then it will al exit with the same excursion angle..." is true. Sorry

Lumia Hints
1. It's often best not to superimpose the different color beams
2. Two or more optical surfaces can produce interesting combinations and the distance between them can be important.
3. Take a piece of plexiglas and form a dimple (or some other shape) and project the lumia through it. (Vary the amount of dimpling, number of dimples, etc.) Warning: Fumes are dangerous!!!
4. Project through an octagonal (or other) faceted crystal (the ones with the back half flat yeald a double star burst)
5. We had a lot of fun with a lumia wheel illuminating a fiber bundle and projecting the output through optical effects (the beam was focused near the lumia wheel for higher intensity into the fibers)
6. reflection off of crumpled aluminized mylar was a nice effect
7. the orentation of the beams relative to the rotation of the wheel(s) makes a difference
8. you might try a take off on the old infinity mirror effect - it might be interesting to vary the angle between the beam splitter(s) &/or mirror
9. and then there's scan through lumia effects...

[Earthnik]

Great - I'll take your word for that ...wast just speaking from the recollection of my "visual" experience so many years ago. Thanks!