Ken, Your original mail has the sentence:
***** It seems to me (Ken) that it should be possible to build such a dial, since the EOT is a function of date, and date lines can be read from many sundials. In principle, I can just re-label the date lines with corresponding EOT values and interpolate. ***** I agree with this and a sample of a dial that's suitable is in Copenhagen, Denmark. See the website of De Zonnewijzerkring. Address below. Follow: Archives 2003 - 2013 Sundial of the month 2006 06-09 Copenhagen. Lable te datelines for a half year left and the other half year right with the appropriate equation of time rounded to e.g. one minute. The dial in Copenhagen has three scales so it can be used for many hours of the day. Best wishes, Fer. Fer J. de Vries De Zonnewijzerkring http://www.de-zonnewijzerkring.nl Molens http://www.collsemolen.dse.nl Eindhoven, Netherlands lat. 51:30 N long. 5:30 E ----- Original Message ----- From: jmikes...@ntlworld.com To: Ken Baldwin ; sundial@uni-koeln.de Sent: Monday, February 04, 2013 9:59 AM Subject: Re: equation of time sundial Ken, I’ve found a couple of small photos of my rather crude device. I’ve posted then in Dropbox at : https://www.dropbox.com/sh/tkxqw7x5mbr1axd/tYOlNAwT60 By coincidence, the 2nd photo shows the EoT is –7.5 minutes and sun’s declination is –7.5 degrees. I hope that makes things clearer. Of course, it’s just really a reverse engineered heliochronometer where you drive the alidade round using a 24 hour clock mechanism (widely available), to keep the spot of light on the analemma. However, I’ve used a graph of EoT and declination instead so that you can read off the two figures directly. Over the course of a year, the spot of light will trace out the analemma. Mike Shaw 53º 22' North 03º 02' West www.wiz.to/sundials No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.2897 / Virus Database: 2639/6078 - Release Date: 02/03/13 ------------------------------------------------------------------------------ --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
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