So now, Mr. Kint, it is your turn to BUILD such a sundial with all its possibilities and not just to talk about it! :-) However it will turn out into an absolutely confusing object of no practical use at all. In Germany there had been a maths professor who tried hard to work out at least some aspects of your list and Gianni Ferraris good list. It is the sundial of J. C. Lüders in 18246 Bützow. You may find some pictures of it easily in my Schwarzes Brett if you scroll down half of the link. http://www.ta-dip.de/dies-und-das/schwarzes-brett.html The local gnomonists are very much excited about this now restored sundial, but sundials which stand/ hang on a public place ought to be beautiful and ought to enjoy people and not to confuse them! Best wishes to you! Reinhold Kriegler * ** *** **** ***** ****** ******* Reinhold R. Kriegler Lat. 53° 6' 52,6" Nord; Long. 8° 53' 52,3 Ost; 48 m ü. N.N. www.ta-dip.de <http://de.youtube.com/watch?v=XyCoJHwzzjU&fmt=18> http://de.youtube.com/watch?v=XyCoJHwzzjU&fmt=18 <http://www.ta-dip.de/dies-und-das/r-e-i-n-h-o-l-d.html> http://www.ta-dip.de/dies-und-das/r-e-i-n-h-o-l-d.html -----Ursprüngliche Nachricht----- Von: [email protected] [mailto:[email protected]] Im Auftrag von Kevin Karney Gesendet: Mittwoch, 17. November 2010 14:40 An: Jos Kint Cc: [email protected] Betreff: Re: What can be calculated with a sun dial? This list - together with all the additions - is great ! But, it would be nice to see which of the many items can be done well by a sundial and how many items would be a 'stretch'. To find the moment of equinox - for example - is theoretically possible - but in actuality is not realistic since the Sun's declination is changing so slowly at those times: (a problem the astronomers of antiquity struggled with). Equally, I think one would be hard pressed to find aphelion & perihelion from a dial - except in a very indirect fashion. But let's get the list complete ! Best regards Kevin Karney On 16 Nov 2010, at 21:38, Jos Kint wrote:
Dear sun dialists, What can be calculated with a good sun dial? Here is a list of 19 topics. Can you add some more items? 1. The hour of the day 2. The day of the year. 3. The solar altitude. 4. The solar azimuth. 5. The longitude of the sun dial. 6. The latitude of the sun dial. 7. The moment of the equinoxes 8. The moment of the solstices. 9. The length of the tropical year 10. The equation of time 11. The excentricity of the earth orbital around the sun. 12. The obliquity of the eclips 13. A compass function 14. The declination of the sun. 15. The moment of the perihelion 16. The moment of the aphelion 17. The moment of the next sun set 18. The Babylonic time 19. The Italian time Jos Kint --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
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