Dear Sundialists: Thank you again for your notes of assistance and comments. This e-mail group is very useful, with responses that are both attentive and thorough. I will try to keep my note brief.
With a great south facing house, the mirror placed half-way up the window, and limiting the hours from 9am to 3pm, fortunately only the 3pm sun dot was appearing on the opposite wall. The markings for the remaining three times in which "sun time" and "watch time" closest agree (Apr 15, Jun 14, and Sep 2), will be shorter and allow me to make lines using three other reference points. My children have enjoyed the process so far -- watching the spot go across the ceiling, and seeing mathematics and science in action! Narrow straight molding (painted white to match the ceiling) placed on these lines (the entire width of the ceiling) to depict the hour lines, will make this dial discreetly decorative, yet functional. With the large amount of interest and enthusiasm generated by this topic, I'll have to take some photos during it's creation, and once completed, share them with the sundial group to demonstrate the whole process and it's success. Judith FYI... For those interested in HUMAN/GARDEN SUNDIALS as well (last summer's project with my children), I've created a "fill-in" worksheet that computes the calculations automatically in "inches" with longitude correction (for Northern Latitudes and Western Longitudes) -- one just needs to know their latitude (and optional longitude and time zone for correction), and the desired size. I've been working with John Hoy to have it posted at his website (http://www.cyberspace.org/~jh/dial/). I will be casting these sundials onto the area schoolyard blacktops in March (before Daylight Savings in April). I believe this "community service" project should be made available to all -- free of charge! -----Original Message----- From: Steve Lelievre [mailto:[EMAIL PROTECTED] Sent: Friday, January 04, 2002 9:58 AM To: [email protected] Subject: Re: Ceiling Sundial I agree, John. At one solstice the EoT is about +2 minutes, and at the other it is about -2 minutes so there would be only a slight discrepancy. Too small to worry about, especially as this is a junior school project and Judith is trying to avoid too much complicated explanation. I like her approach for its simplicity, but there's one potential problem which I don't know how to solve. What happens if the summer dot is on the ceiling and the winter dot is on a wall? How do you draw the straight line connection? I can imagine the method being used by other teachers in the future, and people forgetting to take back Daylight Saving Time for the summer labels, or vice versa. Steve > As it turned out (in my opinion), her original idea was correct. > > John >>> I have the tiny lipstick mirror mounted at my window frame (half way up) >>>, and was told that the easiest way (void of all the mathematical calculations >>> that they would not understand) is to mark each hour in the day during the >>> winter and summer solstices (12/21 and 06/21) -- then connect the "dots". >>> Granted this process takes six months to complete, but it would ensure that >>> all longitude corrections are incorporated, effortlessly.
