Sheshan Astronomical Observatory [Shanghai]

Shanghai Astronomical

Observatory Shanghai（上海） Astronomical Observatory (SHAO) was formally established in 1962 following the amalgamation of the former Xujiahui（徐家汇） and Sheshan（佘山） observatories, which were founded by the French Mission Catholique in 1872 and 1900 respectively. Both came under Chinese government jurisdiction in 1950.

A 40cm double astrograph was built in 1900 on top of Sheshan Mountain, which was the largest telescope in East Asia at that time. It is one of a few telescopes in the world that observed Halley's Comet both in 1910 and 1986.

From 1951 to 1981 SHAO provided the clock-time standard for all China. A new observatory was then established in ShanXi under the auspices of SHAO, which has provided this service since 1981.

The first Chinese-made atomic clock was built in SHAO in 1972, and since then several hydrogen masers made in SHAO have been used at VLBI stations. In the 1980s, SHAO built a 25m radio telescope for use as station in the Very Long Baseline Interferometery (VLBI) network; a 1.56m optical telescope; and a 60cm
satellite laser-ranging system. These three facilities are still in frequent use today.

In 1999, SHAO moved to a new 19-storey building in the Xujiahui district of central Shanghai.