alignment hours (time to have the Sun in a plane) French revolution hours ciao Fabio
Fabio Savian [email protected] Paderno Dugnano, Milan, Italy 45° 34' 10'' N 9° 10' 9'' E GMT +1 (DST +2) ----- Original Message ----- From: Brad Lufkin To: Kevin Karney Cc: Jos Kint ; [email protected] Sent: Wednesday, November 17, 2010 2:44 PM Subject: Re: What can be calculated with a sun dial? The longitude and latitude of the Sun (i.e., the location on the Earth that the Sun is directly above). On Wed, Nov 17, 2010 at 8:39 AM, Kevin Karney <[email protected]> wrote: 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 --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial ------------------------------------------------------------------------------ --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
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