Hi Daniel, > The Equation of Time is zero today so Christmas is a great > time to give, receive or set sundials.
Yes, but don't forget the offset for longitude! > Are the dates of perihelion and solstice close at this time > by coincidence... It's coincidence. The most recent occasion that they were (almost) coincident was in 1246 (see Meeus) when the analemma was symmetric about a vertical axis. The shape of the analemma steadily changes with precession. Sadly, this means that all of us who have designed sundials which incorporate analemmas have to accept that they steadily go out of date. Not that we live long enough to notice! Happy Christmas Frank King Cambridge, U.K. -
