![]() Slutc = solstice_epoch.get_full_date(utc=True) Using the very cool more ISO and TZ aware module Arrow: better dates and times for Python, that can be printed more nicely: import arrow (target, year, Epoch.get_last_leap_second(),Įpoch.utc2local() / 3600., solstice_local.get_full_date(utc=True))) " and local time offset is %.2f hours:\n %s" % Print("%s solstice for %d in local time, if last leap second was %s\n" (target, year, Epoch.get_last_leap_second(), solstice_epoch.get_full_date(utc=True))) Print("%s solstice for %d in UTC, if last leap second was %s:\n %s" % (target, year, solstice_epoch.get_full_date())) Print("%s solstice for %d in Terrestrial Time is at:\n %s" % Solstice_epoch = Sun.get_equinox_solstice(year, target=target) # Get terrestrial time of given solstice for given year Of course, the answer is not accurate down to microseconds, but I also wanted to show how to do high-precision conversions with arrow. Winter solstice for 2018 in local time, if last leap second was (2016, 12) Winter solstice for 2018 in UTC, if last leap second was (2016, 12): ![]() winter solstice for 2018 in Terrestrial Time is at: Using the PyMeeus implementation of those algorithms, and the code below, you can get the following values for the 2018 winter solstice (where "winter" refers to the northern hemisphere). ![]() I am, however, pleasantly surprised to discover that Maimonides (medieval Jewish scholar) proposed an algorithm using the exact same idea a millenium ago.Ī great source for the (complex!) underlying formulas and algorithms is Astronomical Algorithms by Jean Meeus. I also once tried using a library that gave me the solar longitude and implementing a search routine to zero in on the exact moments of 0, 90, 180, and 270 degrees this worked down to the second but did not agree with the times in Wikipedia, so I assume there was something wrong with this approach. Libraries for my favorite programming language also come out to those hardcoded times, so I assume they are using the same or a similar algorithm as the one I implemented. Wikipedia gives these computed out to the minute, so something more exact must be possible. What algorithms or formulas are available for computing the equinoxes and solstices? I found one of these a few years ago and implemented it, but the precision was not great: the time of day seemed to be assumed at 00:00, 06:00, 12:00, and 18:00 UTC depending on which equinox or solstice was computed. ![]()
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