At 01:05 PM 3/27/97 -0500, you wrote: >Hello All, > >I've noticed that with a slender, pointed gnomon set perpendicularly to the >dial's face, the shadow's tip sometimes isn't very distinct. Probably >that's why such a gnomon might be terminated with a knob or ball. > >My questions are, if the gnomon ends with a ball would you measure the >length of that gnomon to the center of the ball or use the overall length? >Would the shadow's tip be easier to determine with one scheme over the >other? > >Thanks for your thoughts, > >Mac Oglesby > > > >Hi Mac,
It seems to me, since the position of the lines on the dial plate are determined in part by the length of the gnomon, the length of the gnomon must be know first. For example if you are designing a dial which is to have a 6 inch gnomon, AND you wish to take advantage of a ball tip, it seems to me you would measure six inches to the ball center and use the center of the ball's shadow as the indicator. Does this make sense? Charles **************************************** * Sundials and The Author * * http://www.geocities.com/athens/1012 * ****************************************
