Hi Roger, Brad, I was just supposing that it was 9 hours before sunset, and guessing that I'd have to add 6 hours to the 3 shown. I AM interested in "hours before sunset" whatever one might call them locally. For instance, at exactly 45 degrees north latitude, when a vertical pole's shadow is pointing exactly west, it is 12 hours til sunset.
Brad, Is it possible in your "soda can" model to have the hours before sunset actually calculated from true sunset, which does vary considerably at higher northern latitudes. I'd also be interested in being able to use a different size can, especially a taller one so that nearer the equator, summertime hours would all fit on the display. The soda can idea is certainly a great one, and the use of the gnomon that doesn't stick out to the side is also a neat idea. Hmmm, Chris Taylor's idea of duplicating the scales, showing AM hours on one set, PM hours on a separate set which would allow one color printing as well as reduce the clutter in winter months, sounds neat too! Yes, I'd like to try your java version as I run a number of operating systems. Thanks much! Edley McKnight From: "Roger Bailey" <[EMAIL PROTECTED]> To: "Edley McKnight" <[EMAIL PROTECTED]>, "Lufkin, Brad MMission Systems\"" <[EMAIL PROTECTED]>, "Sundial Mailing List" <sundial@uni-koeln.de> Subject: RE: Portable Dial Adjusted for EOT and DST Date sent: Thu, 26 Oct 2006 09:47:43 -0700 -----Original Message----- <On the Babylonian and Italian hours you add 6 if necessary? <Edley McKnight Hello Edley, Italian and Babylonian hours are 6 hours from local time only on the equinox. Italian hours start at sunset; Babylonian hours start at sunrise. Both involve 24 equal hours per day. Since sunrise and sunset times vary through the year, the difference from local time varies as well. See my "Timelines.ppt" presentation, a 16.5 MB file at http://www3.telus.net/public/ormerod/NASSVanRTB/ On Brad's "sodaCan.png", I only see the blue lines for Babylonian hours, with black AM and red PM civil times and no Italian hours. It is interesting how these Babylonian hour lines are fairly flat through much of the year and much of the day, diverging most around the summer solstice and noon. Not surprising when you think about it, the altitude of the sun being fairly constant at a given time after sunrise. This is the benefit of concepts like this. They get you to "think about it". Thanks Brad, for the challenge. Roger Bailey Walking Shadow Designs N 48.7 W 123.4 --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial