The Yunnan Observatory

The Yunnan Observatory


Situated 2,014 metres above sea level east of Kunming, Yun-nan province, on the Phoenix Hill (102°47′ E; 25°02′ N), after which it was first named, Yunnan Observatory was founded by the former Astronomical Institute when it had just moved from Nanjing to the city in southwestern China after the outbreak of the country’s War of Resistance against Japan (1937-1945). Senior Chinese astronomers, among them we may mention Zhang Yuzhe, Dai Wensai, Chen Zungui, Gong Shumo and Chen Zhanyun, were at one time or another connected with this Observatory. It was then equipped with only a 10-cm Ross astrograph plus a Hale spectrohelioscope.

After the inauguration of the People’s Republic, the Observatory had been under the joint administration of the Chinese Academy of Sciences and Yunnan University until 1958 when it became the Astronomical Station of the Purple Mountain Observatory. The project of 1956 to improve its equipment involved the installation of a 13 cm refracting telescope for the observation of sunspots. The early 1960’s witnessed the start of satellite tracking at the Station.

Observation of the sun’s chromosphere to be followed by the development of a solar spectrograph began in 1967. Five years later, by a decision of the Chinese Academy of Sciences, the Station was expanded and was given its present name. Construction of its main building was initiated in 1975. Within the framework of the Academy’s long-term programme, the Observatory will be the centre in future for astronomical observations and researches in south China.

A multi-purpose institution with astrophysics as its main subject, the Observatory consists of five separate departments dedicated respectively to stellar physics, solar physics, radio astronomy, celestial mechanics and astrometry. Headed by the director Chen Biao about 200 researchers and technicians are working as its staff members.

The Stellar Physics Department is equipped with a 1-metre reflecting telescope with a Cassegrain-focus spectrograph and a Coude-focus spectrograph, plus such auxiliary apparatuses as a focal reducer, an integrating photometer and an infra-red photometer. Also installed there are a 35 cm reflector and such accessory instruments as a star-image comparator and a micro-densitometer. Chiefly interested in the variable stars, close binaries, novae, peculiar celestial objects and globular clusters, the department extends its scope to include theoretical researches in high energy astrophysics as well as the physics of stellar atmosphere.

Operating a 13 cm refracting telescope, a H-alpha chromospheric-photospheric telescope and a 30 cm horizontal solar telescope with a spectrograph, the department dedicated to solar physics gives descriptions of sunspots and supplies photographs of them, scans the solar flares and also surveys the sunspots’ magnetic fields. Its main interest, however, is in the physics of solar active regions and this embraces such topics as the regions’ fine optical structure and the morphological analysis of it; the correlation between the sunspots, the chromospherical plages and the magnetic fields’ structure on the one hand and the flares on the other; the velocity field of the chromosphere; the periodicity of solar activity; and ancient Chinese documentary records of solar activities.

The department also offers such services as the supply of information of sun- spots and flares, the prediction of solar activity and the ground-based survey of the energy spectrum of the sun.

At the Observatory’s Radio Astronomical Department equipped with radio telescopes varying in the wave-length at which each operates (3.2 cm, 8.2 cm and 10.7 cm), conventional observation of the sun is performed. The development of a 70~130 mc/s accousto-optic solar spectroscope has so far been successful. Efforts are being made at the department better to equip itself for the research on the radio spectra of the sun and the cosmic radio sources, with the final aim of updating its observation to radio spectroscopic studies.

The department joined in the observation of the total solar eclipse of February 16, 1980, during which complete data on all the phases of the event were, obtained with the help of a 3.2 cm radio telescope and another operating at the wavelength of 8.2 cm. Such data in turn made it possible to find the parameters pertaining to quiet solar-radio radiation and high-resolution figures on the – radio radiation over the sun.

The department devoted to celestial mechanics is at present chiefly concerned with the determination of satellite orbits. Its satellite camera with quadraxial tracking frame (SBG), when augmented with a laser ranging system will be able simultaneously to photograph a satellite and to determine how far off it is. Its equipment also includes two GDJ type-printing theodolites and a JSZ-4 dual-frequency Doppler receiver. Researches are being made by the department’s staff on the positioning of the satellite orbits and on geodetic survey with the help of satellites.

The Astro metrical Department of the Observatory, where a photo-electric astrolabe (Mark II), a Zeiss transit instrument and a time-service system consisting of three rubidium clocks and three quartz clocks are installed maintains as its chief task the determination of time and latitude (usine the astrolabe) and the experiments in absolute meridianal positioning on the low or middle latitude (using the transit instrument).An optical shop and a machine workshop are operating as affiliated establishments of Yunnan Observatory. Its Information Department, with a library of more than 20,000 volumes, publishes the Observatory’s proceedings plus supplementary materials. A TQ-16 computer serves all the departments and amateur astronomers may avail themselves of the 35 cm reflecting telescope at the Observatory.

As one of China’s south-western provinces, Yunnan, with its low latitude and high altitude, is considered to be an excellent region for astronomers. The area occupied by Kunming, the provincial capital, and its suburbs offers 320 fine days for the observation of sunspots and more than 2.000 hours for the scanning for solar flares each year and allows the astronomer approximately 200 clear nights annually. Beginning in 1973, staff of Yunnan Observatory made tours to different parts of the province, trying to find suitable sites for future stations for stellar, solar and radio astronomical researches and also making field observation. The Stellar Physical Department’s comparative field observation in the Binchuan prefecture in western Yunnan within a year produced valuable data for the installation of high-altitude stations for stellar observation. This observatory has also spent a few years trying to find round the Lake Dianchi a suitable site for a solar observation station.

Satisfactory achievements have been scored at Yunnan Observatory both in the consolidation of itself and in its researches since the early 1970’s when preparations for it began. Among its discoveries and inventions six have been accorded the rewards of the 1978 All-China Science Convention and the Chinese Academy of Sciences.