unless
they are on the date of a solstice. Tubes in a dial or in a structure
would
light up for a certain time when the sun's declination has a certain
value.
In order for this to be only on one day the tube would have to be quite
narrow
if close to a solstice (declination not changing rapidly).
For examples of illuminating objects INSIDE a building, see J.L.
Heilbron's book
"The Sun in the Church". He shows two examples in the color plates:
Plate 3,The Tower of the Winds at the Vatican and Plate 8, The Shrine of
Remembrance, Melbourne. I could not find much discussion of the first
example.
However, he has some discussion of the Melbourne
application on page 288.
By the way, an excellent guide to this book is found on
www.math.nus.edu.sg/aslaksen/teaching/heilbron.html
Claude Hartman
Arroyo Grande, CA
35.13N 120.58W
Tom Egan wrote:
I'm looking for examples of dials that will illuminate a particular
spot on the dial only on the date (and time of day, preferably) to be
commemorated. I recall running across links to tube-based dials in
the past, but apparently didn't file them away.
Can anyone point me to such dials? I want to show examples to a group
of which I am a member. If they are intrigued by it, the members
might want to commission a dial.
This request is not limited to tubes. Any clever idea is welcome.
You may respond to me off-line if you wish at [EMAIL PROTECTED]
Thanks.
Tom Egan
Costa Mesa California
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