Time of the seasons

[cdeaglejr]

Naturally, the answer to your question depends on the algorithms used to compute the time of the seasons. Since this HP program computes these times geometrically, the prediction depends on the ephemeris used to calculate the position of the sun/earth. It also depends on the fidelity of the root-finder algorithm used to predict the events. Finally, it also depends on the conversion of TDB time to UTC (leap seconds, UTC-UTC1).

Most sources for online information about seasons (IMCEE, US Naval Observatory) provide the data to the nearest minute. This algorithm agrees with these sources to within that minute.

Questions always lead to more questions.

For example, how would you actually measure the time of the seasons?