The modern lunar calendar, also known as lunar calendar, summer calendar or old calendar, is a calendar that calculates time according to the cycle of the moon. It originated in ancient China. After thousands of years of development and perfection, it gradually formed a unique astronomical observation and time calculation system. The discussion is as follows:

1. From a historical point of view, the origin of the modern lunar calendar can be traced back to ancient times. In ancient China, people gradually realized that the change of the moon's profit and loss was closely related to agricultural production through observation and practice of nature. The cycle of the moon is about 29.5 days, while the growth cycle of crops takes longer.

Therefore, the ancients divided a year into twelve months, and each month began with a new moon, so as to better arrange agricultural production. This time calculation method based on the moon is the embryonic form of the modern lunar calendar. From a cultural point of view, the origin of the modern lunar calendar is closely related to the religious beliefs and cultural traditions in ancient China.

In ancient times, people thought that the moon was a symbol of the gods, so many sacrificial activities and folk customs were included in the lunar calendar. For example, the Mid-Autumn Festival is a traditional festival in China to worship the moon god. On this day, people will hold activities such as enjoying the moon and eating moon cakes to express their admiration and gratitude for the moon.

4. From a scientific point of view, the origin of modern lunar calendar is closely related to the astronomical research in ancient China. Ancient Chinese astronomers discovered the relative position relationship among the sun, the earth and the moon by observing the movement law of the moon, thus establishing a complete astronomical observation system.

This system includes not only the observation of the moon, but also the observation of the sun, planets and other celestial bodies. Ancient astronomers in China have accumulated rich astronomical knowledge by studying these celestial bodies, which laid the foundation for the development of modern astronomy.

The difference between lunar calendar and new calendar

1. From a historical point of view, the lunar calendar, also known as the lunar calendar or the summer calendar, originated in ancient China and can be traced back to the Xia Dynasty. This is a calendar that calculates time according to the period of the moon. The new calendar, also known as Gregorian calendar or Gregorian calendar, originated in ancient Rome, and it is a calendar that calculates time according to the period of the earth's orbit around the sun.

2. From the calculation method, the calculation of the lunar calendar is mainly based on the change of the moon's profit and loss, which divides a year into twelve months, and each month begins with a new moon. The new calendar takes the earth's revolution around the sun as a year, and divides the year into 365 days, adding one day every four years (leap years) to make up for the time deviation caused by the error of the earth's revolution around the sun and 365 days.