Dan-- Evidently those two sources you named got their result from the same other source, which had made an error. ...or else one of those two sources got their result from the other.
If the two years are separated by a leapyear (but 1930 and 1931 aren't), then there could be a 3-day difference in the correspondence between date and ecliptic-longitude. But, since there was no leapyear between those two dates, there was just the 1/4 day displacement that occurs at the end of a common-year. That wouldn't be nearly enough to cause that difference in sunrise or sunset times. ...or a sufficient difference in the EqT. So, evidently someone's error got copied and thereby propagated. 10 Tu Pisces 7th Februarius 25th On Tue, Feb 25, 2020 at 2:00 PM Dan-George Uza <cerculdest...@gmail.com> wrote: > Hello all, > > While doing some research for a paper, a friend of mine noticed peculiar > differences regarding sunrise times for his city (Alba Iulia, Romania). > They occur both on TimeAndDate.com as well as suncalc.org and -so far I > can tell- only in Romanian cities (Berlin and Vienna are okay). > > I figure sunrise times should be pretty much the same except for the leap > year cycle, but for example between December 1st 1930 and December 1st 1931 > the times differ by more than 15 minutes. What could be the cause? > > I also looked at Gian Casalegno's Sun Ephemeris and all the times check > out neatly there. > > -- > Dan-George Uza > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > >
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