Hi John, Fred and All, Observation #1 -- We return to the correct hour tonight when we set our clocks back one hour.
#2 The line for an equal angular dial has been interesting to me since I first read about it in Fred's Sciatheric Notes. After he revisited the concept at the NASS conference, I wrote an Excel spreadsheet to draw the curve. I would be happy to send a copy to anyone interested - it is 48K long. Fred Sawyer noted two variables -- (1) where the center of the equant circle is placed on the horizontal dial and (2) the ratio of size of the hour in the two dials. You (and I) have noted a third variable - the starting lines. I picture the dial as a locus of points where a horizontal dial line intersects an equal angular line (they must have different centers) . The starting line on the dial will intersect more than one line on the equal angular set -- so you have a choice of starting points. It becomes more interesting as the increment becomes less. Forgive my weak explanation -- it is difficult to describe. Warren Thom (41.649 N 88.096W) John Carmichael wrote: > Hello again: > > I played around some more drawing a horizontal sundial that has equally > spaced hour lines and was able to find three different designs that seem to > work. I used the same geometric technique using little circles of equal > radii that I described in my first mailing on this topic. Because the > circles in the early morning and late afternoon interset the adjacent hour > lines at two points I noticed that different versions were possible. And > low and behold, version C looks a lot like the version Fred talked about at > the conference! (You were right Fred!) > > I used one hour time lines as before to keep the drawings simple, but as > Fred pointed out, if you use smaller time increments, the drawings become > even more precise. > > I am e-mailing this new drawing which clearly shows all three versions to > those people who requested drawings. If anyone else would like me to send > this to them, please let me know. > > John Carmichael
