With a sun dial you can measure at least 24 astronomic, religious and other parameters: 1. The time of the day; 2. The day of the year; 3 and 4: The geographic coordinates longitude and latitude of the sundial; 5. The time equation; 6. The moment of the vernal equinox; 7. The moment of the autumn equinox; 8. The moment of the summer solstitium; 9. the moment of the winter solstitium; 10. the moment of the perihelion; 11. the moment of the aphelion; 12. The excentricity of the earth orbital around the sun; 13. The length of the tropical year; 14. The latitude of the tropics; 15. The altitude of the sun at each moment; 16. The azimuth of the sun at each moment; 17.The moment of sun set; 18. the moment of the sun rise; 19. the length of the spring, the summer, the autumn and the winter; 20. the babylonic time; 21. the Italian time; 22. The canonic moments (the vespers, the matins,) 23. The moment of the islamic prayers; 24. The analemma of 12 hours.
The precision of these paramerters depend on the size and the structure of the sundial and the number of observations, eg. the excentricity of the earth orbital around the sun ( at this moment e = 0.0167) can be measured with a simple sundial with an error of less than 1%. You just need much patience... Sometimes it takes several hunderd measurements ( = some years of daily observations). Jos Kint De Pinte, Belgium From: Thibaud Taudin Chabot Sent: Monday, January 15, 2018 12:19 PM To: Sundial sundiallist Subject: Re: The utility of sundials today. A sundial is a timing device entirely driven by solar power and has an automatic and precise reset after powerfailure....... ;-) At 20:26 14-1-2018, Willy Leenders wrote: When I talk about sundials, I get the question: "What utility can sundials have today?" In order to be able to give an answer as diverse as possible, I would like to receive your answer to this question Willy Leenders Hasselt in Flanders (Belgium) Visit my website about the sundials in the province of Limburg (Flanders) with a section 'worth knowing about sundials' (mostly in Dutch): http://www.wijzerweb.be --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial -------------------------------------------------------------------------------- Th. Taudin Chabot, . tcha...@dds.nl -------------------------------------------------------------------------------- --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
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