Please forgive me -- I am not well-versed in sundial lingo, although I think I have a pretty good grasp of the concepts.
I made a discovery today that is new to me, but perhaps not new to you all. I have never seen it published anywhere. I have recently constructed a small wooden horizontal sundial. The gnomon is 1/4" thick. So, on calculating my hour lines, the lines on the left are 1/4" offset from the ones on the right. So far so good. Except that I was pretending to be the sun as I looked down on my new sundial to see where my shadow would fall, and I noticed that for hour lines south of (where the gnomon intersects the dial face -- I'm sure there must be a name for this), the gnomon edge which cast the shadow was not the one I expected, but the other one. I.e. If the sun is northwest of the sundial, the west edge of the gnomon is the one casting the relevant, time-telling shadow. If the sun is southwest of the sundial, the east edge of the gnomon casts the shadow. If the sun is in the southeast, the west edge of the gnomon casts the shadow. If the sun is in the northeast, the east edge of the gnomon casts the shadow. Am I right so far? And so it would seem that hour lines that lie south of where the gnomon intersects the dial plate should be drawn to intersect the opposite edge than lines that lie north of it. Perhaps someone could rephrase all this for me, and then tell me whether I'm correct or not? Thanks, Rod Heil ~41.3 N 105.5 W __________________________________________________ Do You Yahoo!? Great stuff seeking new owners in Yahoo! Auctions! http://auctions.yahoo.com
