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Thu, 5 Mar 1998 10:22:40 -0500 |
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> We wish to construct a light show and project it on to a high ceiling and high
> side walls in the main lobby of a museum. The graphics will be silhouettes of
> Chinese characters and dragons. We wish these to "dance" over the heads of
> viewers.
> I know that there are expensive ways to do this with computers, etc..
> But does anybody know of a simpler manner that would consist of a stencil cut
> out revolving around a light source?
In our planetarium, we often use simple 'brute force' projectors for
similar effects. A typical example is the common planetarium 'cloud'
projector.
What you need to do is find a light source that is as close to a
point-source as possible. We've had best luck with low-voltage signal and
automotive lamps. The idea is that you want a *really* short fillament.
If the fillament is too long, this won't work well, and the images will be
very fuzzy.
What we usually do is put the lamp inside a rotating plexiglas dome, and
paint the images we want to project on the outside.
Another technique is to have the images on a lazy susan, and spin the disk
in front of a window with the lamp behind it.
-j
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