This is very nice, but it appears that it will only work during the summer half of the year between the equinoxes, because the side triangles will block the sun from the underside of the disk during the winter half. I prefer teaching sundials that are equatorial and can be compared to a globe dial for all seasons. (I use a small globe with a rod stuck up the axis and protruding at both poles, and an equatorial disk similarly mounted and adjustable for latitude.)
Sara 42°21'N, 71°13'W Sara J. Schechner, Ph.D. David P. Wheatland Curator of the Collection of Historical Scientific Instruments Department of the History of Science, Harvard University Science Center 251c, 1 Oxford Street, Cambridge, MA 02138 Tel: 617-496-9542 | Fax: 617-496-5932 | sche...@fas.harvard.edu<mailto:sche...@fas.harvard.edu> http://www.fas.harvard.edu/~hsdept/chsi.html From: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] On Behalf Of Astrovisuals Sent: Tuesday, April 26, 2011 6:06 PM To: sundial@uni-koeln.de Subject: Sundials for teaching I would like to put my "Sun Disc" forward as a universal equatorial adjustable dial.. with lots of helpful instructions! Extra instruction sheets are available to help teaching the concepts behind sundials. Haven't reaped many rewards so far, though! http://www.astrovisuals.com.au/SunDisc.html * David Widdowson, ASTROVISUALS, * * 6 Lind St, Strathmore, 3041, AUSTRALIA * Ph/fax: 61- (0)3 - 9379 5753 * EMAIL: m...@astrovisuals.com.au<mailto:m...@astrovisuals.com.au> WEB: http://www.astrovisuals.com.au
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