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Hi Mike,

Since you are not intending to project a solar image, you may well 
consider a simple heliostat
for gathering sunlight and projecting it through a slit and prism – you 
wouldn't need a ceolostat.

Modern interests in harnessing solar power for lighting and energy 
generation has led to
much experimentation with heliostats. You may get find more info by 
contacting the
National Renewable Energy Laboratory. A number of companies have also 
sprung up
over the past few years that use microprocessor controlled mirrors to 
direct sunlight
into buildings, such as Bomin Solar and InSpira. I don't think you'll 
have a
problem getting the technology off-the-shelf.

Exhibitwise, I think an image of the sun would be a much more 
interesting
image to see and interpret if you are going to go to the trouble and 
expense of tracking the sun.
Honolulu certainly as many hours of cloudless observation time, and I 
distinctly remember
how awestruck visitors were when they observed the sun and sunspots via 
that big old
refractor of the Museum's that was jury-rigged as a solar observatory.

Hawaii is the "Rainbow State." If you really just want to project a 
rainbow – cheap and
nearly maintenance free – you may want to consider a halogen bulb, slit,
and prism / diffraction grating combination so it will appear rain or 
shine.

Aloha,
Richard Duggan

Dare Design
45-1112 Haleloke Place
Kaneohe, HI 96744
(808) 235-9585

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On Nov 9, 2005, at 5:35 PM, Mike Shanahan wrote:

We are trying to find a way to project the sun into a museum building
and on to a prism to create a rainbow effect.  Does anyone have advice
on what it takes to get a tracking device that would work year-round to
project the sun's light into a building?  We of course have telescopes
that can be set up to do a similar job on a daily basis but this would
be a more permanent installation and one that would, ideally, not
require daily adjustment.



I recall seeing a device at the space museum in Rio de Janeiro that
projected the sun onto the museum floor...I should have taken more
notes!

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