Dear Dave, Your calculations are close, but being 1.9 degrees east of your meridian, this makes your dial run fast by 7 minutes, 36 seconds, not including the equation of time. Each degree of longitude from the meridian affects the dial by 4 minutes.
So, your dial should be 7' 36" fast by your location, plus 3' 44" fast for what you give as the EoT, for a total of 11' 20" fast on may 13. If your dial is accurately made, and you are able to read the sundial time to within a few seconds (you may be able to do this if you know how to use a shadow sharpener), you can calculate how "misaligned" your dial or wall is using www.precisionsundials.com/sundialalign.exe . It works best near the solstices, so next month would be the ideal time to try it out. Bill Gottesman www.precisionsundials.com ----- Original Message ----- From: [EMAIL PROTECTED] To: sundial@uni-koeln.de Cc: [EMAIL PROTECTED] Sent: Monday, May 14, 2007 7:10 PM Subject: South Vertical Declining dial Dear Sirs: Here's my problem. When my south vertical declining dial reads 11:00 my watch (set by Click here: The official US time ) reads 10:50, when it reads 12:00 my watch reads 11:50 at 2:00 the watch reads 1:50 and at 3:00 the watch reads 2:50. The location of the dial is at 33.44N and 118.1W, the declination of the wall is between .1 degree and 2.7 degrees west of south depending on the accuracy of the measurement. I used two methods one from www.precisionsundials.com/walldeclination.exe which produced the .1 degree and the other from Click here: Sundial Sculptures by John Carmichael, Jr. which produced 2.7 degree based on the measurements I gave him. John was extremely helpful and even sent dial plate with gnomon measurements. The times above were taken on 5/13/07. The standard time meridian in my area is 120 degrees, me being at 118.1 = equals approximately 4 minutes and the EOT on the 13th is 3:44 (from table A.1 in Sundials - Their Theory and Construction, by Albert E Waugh, that's still only adds up to 7:44. If this is the wrong forum for this kind of problem please let me know, any and all help is appreciated. Thanks Dave Koller ------------------------------------------------------------------------------ See what's free at AOL.com. ------------------------------------------------------------------------------ --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
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