June 20 (or 21 or 22) a.k.a the
Summer Solstice was the longest day of the year in some countries.
For various reasons (please specify in the solution) the date varies from year to year, but (good news!) it is fully predictable.
Please describe how to find the dates of
Solstices and Equinoxes in this century and for that matter for any year, but list them for this century, to allow comparison to published lists, specifying the name and location
of your choice, Northern or Southern Hemisphere and the Time Zone.
Default: Paris, France.
(In reply to
No Subject by Charlie)
Hidden by the use of MATLAB's built-in conversion of Julian Date to ordinary Gregorian calendar date, is how the conversion is done. Say you've come up with the JD (which is actually a sequential ordering of the day with fraction); remember that the fractional part is zero at noon, so round the JD value to the nearest integer to get an integer that is changing at midnight GMT; call that integer Z. Per Meeus's books the conversion to M, D, Y is:
a = floor((Z - 1867216.25)/36524.25)
A = Z + 1 + a - floor(a/4)
B = A + 1524
C = floor((B-122.1)/365.25)
D = floor(365.25*C)
E = floor((B - D)/30.6001)
The day of the month is B - D - floor(30.6001*E)
The month number, m, is E - 1 if E <= 13
E - 13 if E > 13
The year is C - 4716 if m > 2
C - 4715 if m <= 2
|
|
Posted by Charlie
on 2021-07-06 15:51:50 |
re: No Subject
