quarta-feira, 21 de junho de 2017

Astronomy picture of the day - 2017 June 21 - A Sundial that Shows Solstice

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A Sundial that Shows Solstice 
Image Credit & Copyright: Jean-Marc Mari
Explanation: What day is it? If the day -- and time -- are right, this sundial will tell you: SOLSTICE. Only then will our Sun be located just right for sunlight to stream through openings and spell out the term for the longest and shortestdays of the year. But this will happen today (and again in December). The sundial was constructed by Jean Salins in 1980 and is situated at the Ecole Supérieure des Mines de Paris in Valbonne Sophia Antipolis of south-eastern France. On two other days of the year, watchers of this sundial might get to see it produce another word: EQUINOXE.