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Hi Tom:
Is a skylight hole in your roof possible?
This would eliminate most of your problems with mirrors. You don't need a
flat roof. A skylight hole could be used for any of the interior dials I
mentioned.
----- Original Message -----
Sent: Saturday, January 03, 2004 11:36
PM
Subject: Sundial inside a room, but room
is inside a canyon!
I have a nice, south-facing room. The trouble is, my
neighbor's two-story house is about 10 feet away, due south.
Consequently, if I cut an aperture in my wall, the sun would find it
only mid-summer. The rest of the time, my neighbor's roof would block
the sun. Demolishing his second story is not an option, he
says.
I thought of using mirrors to relay the sun's rays down the
canyon between our houses, much as a periscope would. This could be an
extension of John Carmichael's reflection sundial (#4 in his reply to
Ronit) Several problems with that, since the horizon-to -horizon and
season-to-season arc of the sun would require either
- A small mirror on top and a huge mirror at the bottom end, plus a huge
aperture, or
- A large set of individually aligned small mirrors on top that are
focused on a small mirror at bottom.
Then I thought of a bundle of
optical fibers to carry the sun position information down to a dial or display
inside the room. This might be considered an extension of John's #3
projection dial. A little better, but still requiring precise aligning
of hundreds of individual fibers at the top end. Plus the disadvantage
of losing some resolution and brightness because of quantizing the information
(in discrete fibers) and then transmitting it through glass instead of
air.
Finally, I remembered Mike Shaw's clever implementation of an
Indoor Dial he reported on October 29 (or thereabouts), 2000. He used a
150 mm diameter, plastic sewer pipe to hold the fibers in an equatorial
semicircle. While he could have installed enough fibers to give 5-minute
resolution, he chose to start with just 15-minute resolution. The
display ends of the fibers were arranged around the periphery of a clock
face. He reported that plenty of light gets down to the
display.
This isn't quite what I'm looking for, though, as I'd like the
equivalent of a garden sundial in my room whose gnomon casts a shadow.
I think I can now properly formulate my question: Is there a way
to get the sun's rays down to my room so I can have them illuminate an
ordinary sundial? (Without demolishing my neighbor's house or spending a
ton of money?)
Tom Egan
33.642 N, 117.943 W
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