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
Nachricht-Von:
[EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]Im
Auftrag von John CarmichaelGesendet: Tuesday, August 14, 2001
4:15 PMAn: [EMAIL PROTECTED]Cc:
sundial@rrz.uni-koeln.deBetreff: Re: diameter of reflected sun
image
Hi Fritz
Good to hear from you! What an interesting
