Dan, Steve
Regarding the exact time of intersection: It requires a rather
interesting problem of simultaneously minimizing EOT and declination
between spring and fall dates. Fortunately I have a spread sheet that
implements the calculation of EOT to within a second or so and likewise
precise declination. I set up the difference of EOT(spring) - EOT(fall)
and DEC(spring)-DEC(fall) as a pair of 2D tables using date/time
variables. To see small changes, I multiplied the DEC error in degrees
by x100 and looked at EOT error in seconds.
For this year, the result to the nearest hour is 11 April, 7:00 UTC and
28 Aug, 17:00 UTC corresponding to Julian Dates of
2458219.79167 and 2458359.20833.
Regards,
Bob
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