Time and the Calendars

29 days 30 days 7-day week astronomical average Babylonian Babylonian calendar beginning Boll and Gundel calendar-makers calendrical practices called Celestial Equator century BC Chinese circa conjunction constellation convention Denderah ceiling divided earlier early Earth Ecliptic Egyptian civil calendar embolistic February fixed stars fractions full Moon Greek Gundel pictures haab Hellenistic Hindus Hipparchos Indian intercalary month intercalation intervals Jewish Julian calendar Julius Jupiter Kalends later Latin longitude lunar months lunar synodic months luni-solar calendar Macrobius meridian crossing Meso-American Mesopotamian Metonic Cycle midnight millennium BC minutes months of 29 nakshatra Neugebauer night number of days number system observer occurred Parker perhaps period planetary week pre-Julian precession Roman Sanskrit schematic months seasons sexagenary cycle sexagesimal sidereal sidereal period Sign solar months Sothic heliacal rising Spring Equinox suggests Summer Solstice Sun's sunrise sunset synodic month temporal hours third tithi tropical twelve tzolkin Venus Waerden whole days Winter Solstice zodiacal constellations