I don't really know, but I would think that the zero level is chosen so that the total area of the EQT curve above the line matches that below the line. This would make the annual mean of the EQT would be zero minutes.
At 23:02 3/04/2000 -0400, [EMAIL PROTECTED] wrote:
4/3/00 Does anyone know why the equation of time is indexed to zero on 9/1, 12/25, etc.? That is to say, when the clock was originally being indexed to the sun (17th century?), why did they pick this set of dates as the zero point? Why not, for example, set the clock to where the analemma crosses itself, or to one of the solstices, or equinoxes? I'm sure there is a good reason, but I haven't been able to think of it. Maybe it has to do with indexing the clock to sidereal time, and not to sun time. Any takers? Bill Gottesman Burlington, VT
Regards Hank de Wit Adelaide Australia 34.9231S 138.6206E <B>[EMAIL PROTECTED]</B>
