Solar calendar
A solar calendar is a calendar whose dates indicate the season and so are synchronized to the declination of the sun. The mean calendar year approximates some form of the tropical year (typically either the mean tropical year or the vernal equinox year).
The following are solar calendars:
Every one of these calendars has a year of 365 days, which is occasionally extended by adding an extra day to form a leap year.
The following are lunisolar calendars; they have dates that also indicate the moon phase:
Calendars that are not solar calendars, include the Islamic calendar which is a pure lunar calendar and calendars synchronized to the synodic period of Venus or to the heliacal risings of stars.
Categories: Calendars