Well, my guess about the diagonal line is that the wall declines to the south
east, and that the diagonal line defines the shadow path of the style's tip
on the equinoxes. I ain't got no idea what the numbers are all about. Bill
Gottesman, Burlington, VT
In a message dated 8/13/2001 7:46:08
Hello John:
A friend who does optical design pointed out that a pin hole can act
as a lens.
At one time there was an "F100" school of photography.
The idea is that a hole, flat piece of glass or a mirror operated at
f # 100 or higher acts as a lens.
The f# = (diameter of the optic) / (distance
On Mon, 13 Aug 2001, John Carmichael wrote:
Knowing the apparent diameter of the sun, the size of the mirror, and
the distance from the mirror to the ceiling, how could I calculate the
diameter of the sun spot?
Take the limiting case, of a (nearly) zero-diameter mirror. This is
exactly the
A specialist in analemmatic sundials is Frans Maes.
You can find his 'analemmatic extra info' on
http://www.biol.rug.nl/maes/zonnewijzers/welcome-e.htm
Willy Leenders
Robert Terwilliger wrote:
Hi Dialists,
Can anybody in the Philadelphia area help this lady?
Hi Bob -
I work for the
The
classical experiment using a mirror to detect minute rotations is not by
Michelson and Morley, who used an interferometer, but by Cavendish, who measured
the universal gravitaional constant in the lab. But the technique has been
used often.
--Art
Carlson
-Ursprüngliche
