The measurement station and the Observatory

After the establishment of the Zhou Dynasty, Zhouwu Wang believes that Songshan is a day room, and then to heaven. Wang successor, Regent of the Duke of Zhou Wu will comply with the building of new Luo yi. In the era of divination, the one hand, in Luo Yi in "seeking to build, and Wang Fu people", "the king shall dwell in the earth" public opinion, hand the name of development of agricultural production calendar, under the banner of Chinese began the first time in the history of large-scale astronomical measurement. He was in the country set up five points in the table, in Yingchuan Yangcheng, began to build Chinese tree, table, measuring the shadow. By measuring, day in and day out year after year, the Duke of the measured data is recorded one by one, found a shadow from long to short again from short to long period, and find out the seasonal changes according to the change of shadow every day in the winter and summer that it is short of it. Then, he took a period called a year, and the longest shadow that day as the winter solstice, the shortest shadow that day as the summer solstice, the two time points of length changes are called the vernal equinox and autumnal equinox, so according to the seasons there according to the guidance of agricultural production according to.

In ancient times, because of technological backwardness, underdeveloped productivity, low level of awareness, people think that North and South Tianyuandifang, three million in the earth. Compared with the eight feet long meter out of the shadow, shadow that "one inch, the difference of thousands of miles". Using the standard method of Zhou soil deep, is king, for in four, inspection, found the Yangcheng Dengfeng summer solstice table. A foot five inches long, in the north and South on the center of the earth, so that here for the world, the center of the universe. Because of this, the Duke sent to Zhao Gong in Yangcheng Taibao from only more than 100 in Luoyang City to observe the terrain, then flied to Luoyang City Construction capital. The permit for Yangcheng, and the Central Plains area known as Chinese Yuzhou, known as Zhongzhou, known as the Chinese nation. Chinese, China, Zhongzhou, and Turkey, Central Plains, mountain, transit words "in" the resulting. Even the Henan dialect does not say "good" or "no", and says "not in the middle"".

Tang Kaiyuan twelve years (724 years), the famous astronomer I-Hsing was ordered to "test generation from the calendar, modification of the new calendar", once again organized an unprecedented astronomical survey, he is still in Dengfeng Yangcheng as the center of observation point, and according to the survey results, a strict structure and a logical "premium calendar". Nangong said his subordinates to save Duke measuring shadow by the old system, then the changes in Chinese wooden table for the stone table Guishi Zhou period, and "five characters engraved" the Zhougong sundial taiwan.

To thirteen yuan (1276), Kublai appointed famous scientists Guo Shoujing, Wang Xun and other people to carry out large-scale astronomical observation activities to improve and revise the calendar, which is the famous "Four Seas" test". At the beginning of the calendar, Guo Shoujing was keen to begin by suggesting that actual observation was the principle of managing the calendar. He said, "the calendar is the test, and the instrument of measurement is not the instrument."." So he is concentrating on developing new astronomical observation instrument, the guiding principle in brief and practical, he has created a simple device, high table, scaphe, Jing Fu and other eighteen kinds of astronomical instruments, and Sr and high surface are the two most important instruments. The observatory is actually Guo Shoujing to create a high table improvement. In order to establish a more accurate calendar, Guo Shoujing Kublai to voice said: "in Tang Dynasty, a monk had ordered that the world Nangong thirteen areas of field observations, and today the national territory is more general than the Tang, need to go to the remote place test. Otherwise, Riyuejiaoshi scores of different time, different length of day and night, the moon and stars to the sky under different, North and South can first made table direct measuring shadow." The wise Kublai approved his proposal, and in sixteen yuan (1279), he set up fourteen road magistrate, and started several ways to carry out astronomical observation throughout the country. According to records, Dengfeng Yangcheng is an observatory in the "Four Seas" test, and it was the central observation station of the country at that time. To sixteen yuan in March, by Guo Shoujing, are mostly started, after Henan, arrived in the South China Sea, travel thousands of miles, to master this road test in Dengfeng, had personally presided over the Yangcheng Yangcheng observation, "Arctic thirty-four degrees too weak" conclusion. Today, the Dengfeng Observatory Beijing Observatory was founded by Guo Shoujing two permanent high table. The Dengfeng Observatory is a city with a variety of functions, such as timing and measuring shadow star Observatory, is the "universal test" in the twenty-seven seat observation station is still preserved in the world only one. The observatory is not only our country's extant Observatory, is also one of the world's most ancient astronomical sites. The observatory now has 700 years of history. It is the longest, which is one of the world's best preserved ancient astronomy building complete, the history of our country is evidence of astronomical science development summit, is currently the oldest Chinese an observatory.

Through field observation in Guo Shoujing Observatory, mastered the earth works, and accurately measure the twenty-four solar term, especially the exact time of the summer solstice, winter solstice and equinox, in Yuan seventeen years (1280) developed the world's most advanced calendar - "calendar time", a return the length of the calendar year is 3652425 days, and today the 365.2422 day 365 days 5 hours 49 minutes and 12 seconds, with the determination of modern science huiguinian length 365 days 5 hours 48 minutes 6 seconds compared to one year only 0.0003 or 26 seconds, and now the world's common Gregorian calendar than a second not bad, but it was more than 300 years earlier. "Calendar time" into Kublai Khan, according to the "book of history" in the "Jingshouminshi" one named "calendar time". "Time service" used for 364 years, is the longest in our history the implementation of the calendar. Later, the emperor of the Yuan Dynasty also under the edict to "calendar time" given to Korea (now North Korea, Japan), Annan (now Vietnam) and other countries.