I've planed to celebrate winter solstice at work with a group of people dedicated to look after and promote the Citadel of Roses. We'll do it with a "Stone Aperitive" following the tale of Mullah Nasrudin, where every body brings something and everybody enjoys everything. Looking for the date I've found it's full moon as well so extra champagne, that in Catalan is cava, will be brought Best wishes to all sundial lovers and happy journey to 2011, full of fortune, full of knowledge, ( free translation of "Journey to Itaca" by Cavafis) Roser
2010/12/20 <[email protected]> > The date of earliest sunset depends on Latitude and is not > always Dec 14. See: http://www.idialstars.com/eass.htm > > > > > > Dear Colleagues > > > > In the depths of a freezing Northern winter, there's time to think about > > days of special interest. There are six significant solar dates around > > this time of the year. > > > > Three are special and probably known to all... > > 21st December - half an hour before midnight - the Winter Soltice > > 25th December - not only Christmas day, but one of the four days in > the > > year when the equation-of-time is zero. > > 3rd January - Perihelion when the Earth is closest to the Sun, > > > > One day is perhaps of interest only to the serious heliochronometer > > user... > > 23rd December - the day when the equation of time is changing at > its > > maximum rate of almost 30 secs/day > > > > Two days are nothing more than obscure, except to the numerically > obsessed > > - or to those who like strange questions to ask on quiz nights.... > > 14th December - the day on which the Sun sets earliest in the day > > 29th December - the day on which the Sun rises latest in the day > > See the graph below. If you wonder why this is so, it is because there > are > > two effects in play (a) the daily change in sunrise/sunset as a result of > > declination change is minimal around the solstice and (b) the effect of > > the equation of time with its large eccentricity component as the Sun > > races forward towards perihelion. > > > > p.s. the graphs are for 54 degrees North latitude; the y-axis scale will > > change at other latitudes. > > p.p.s. dates are UT - so they may vary with your local longitude. > > > > Have a wonderful Christmas season. > > > > Kevin Karney > > > > --------------------------------------------------- > > https://lists.uni-koeln.de/mailman/listinfo/sundial > > > > > > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > >
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