Bill I think that it was not a choice to index to those dates but instead to place the analemma such that the number of days that the EoT is positive is the same as the number of days that the EoT is negative. If the analemma is displaced this balance cannot occur. I discuss this average on my page at
http://www.wengersundial.com/math/analemmaCalc.html Dan Wenger >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 Daniel Lee Wenger Santa Cruz, CA [EMAIL PROTECTED] http://wengersundial.com http://wengersundial.com/wengerfamily
