September 2009 18 What is the lunar calendar?

According to the perpetual calendar, we know the solar calendar, September 2009 18, the lunar calendar, July 30, 2009, Ugly, Year of the Ox. The solar calendar, that is, the Gregorian calendar, is a common calendar in most countries in the world. This is a calendar based on the movement of the earth around the sun. The lunar calendar, also called lunar calendar, is a calendar based on the change of the moon's full and short periods.