Great idea Gianni!
Will have to try it. Thanks John C. On Fri, 5 Jul 2002 18:39:57 +0200 Gianni Ferrari <[EMAIL PROTECTED]> wrote: I have read with a lot of interest the numerous and very interesting messages that concern the Shadow Sharpener and I would like to make a little observation. This doesn't concern the beautiful sundial of John Carmichael and the clever methods described for the the use of the pin-holes sharpener, but perhaps it could interest someone for other applications. To see the image of the Sun together with that of a distant gnomon we can use a different approach instead of using a S.S. If we could put our eye on the plane (for instance in the place of a hour line), looking toward the Sun (when the shadow of the gnomon passes on the line) we would see the disk of the Sun and the gnomon with a great sharpness. Because we cannot put our eye on ( or under) the plane, we can put there a small mirror and look in it directly: obviously the eyes have to be protected or with eclipse glasses or with a Milar filter or with a welding glass, etc. To decrease the quantity of the light reflected it ispossible to replace the mirror with a simple window glass. With some patience we can see the sharpest possible image of the disk of the Sun and of the gnomon without any defocusing phenomenon . With a solar filter for binoculars or for a small telescope, the image can also be magnified and observed with a very good precision. Best wishes Gianni Ferrari 44 39' N 10 55' E Mailto : [EMAIL PROTECTED] - -
