出典:Wikipedia
出典:『Wikipedia』 (2011/05/13 17:37 UTC 版)
The Julian calendar began in 45 BC (709 AUC) as a reform of the Roman calendar by Julius Caesar. It was chosen after consultation with the astronomer Sosigenes of Alexandria and was probably designed to approximate the tropical year (known at least since Hipparchus).
the Julian calendar
a calendar
the lunar calendar
the lunar calendar
the solar calendar
a sheet-calendar
the old calendar―the lunar calendar
the new calendar―the solar calendar
the reformed Julian calendar now in use, called Gregorian calendar
the method of reckoning time according to the Gregorian calendar