Hello All, Those of you at the NASS Montreal convention will recall my presentation on a new method for aligning a sundial, including a nifty program which makes the process simple. Even if you forgot everything I said, I think you will still recall my struggle with the bowling ball demonstration.
I have just put the program on my website (www.precisionsundials.com). It is called SundialAlign! and should (I hope) run on Windows95 or later. You just enter 3 (or 4) readings off your dial compared to a clock, and it calculates how far your dial is misaligned from the Celestial North Pole, and then tells you how to adjust it to set it properly. The beauty of this method is that you can then take successive measurements and keep refining your adjustments until it is just about perfect. This is the only alignment method I know of that utilizes feedback. It works in the northern and southern hemispheres, and for all right ascension (common) dials. You don't even have to know what location your dial is made for. The principal drawback is that it not usable near the equinoxes because tiny errors in reading your dial (even a few seconds) greatly effect the results when the sun's declination is small. It works great, however, near the solstices. Using this method in July I was able to align my dial to read Daylight Savings Time correct within 20 seconds all day long (a photo of this is in the program. That particular dial self corrects for Eot). Give it a try and let me know what you think! Bill Gottesman Burlington, VT 44.4674N, 73.2027W
