On Mon, 23 Dec 2002, Mac Oglesby wrote: > With respect, I have to disagree with John Davis. If you rotate a > polar dial around its polar axis (or any axis parallel to the > Earth's--an edge of the dial plate, for instance)
(Which of course, IS rotation about the gnomon axis, PLUS translation in the plane normal to that axis) > by 15?, each hour > line will be one hour off--ahead or behind depending upon which way > you turned the dial. Should you want an 8 minute change, twist the > dial 2 degrees. Etc. At least that's how my polar dials seem to work. That's the way I thought it worked, also... Something about it does bother me, particularly when I consider a dial already incorporating EOT and longitude correction (with a date/time grid and an index on the gnomon), but I can't quite put a finger on it! Dave -
