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With the assistance of advance technology in the modern world, we find no difficulties in telling the time, observing the sky and predicting the weather. In the ancient China, however, people were also well known for their ingenuity in designing astronomical instruments, which facilitated them to forecast seasonal changes accurately and to device their own calendar.

From tomorrow (November 16) onwards, we will have a golden opportunity to appreciate the ancient Chinese wisdom. A special exhibition "Ancient Chinese Astronomy", to be staged at the Hong Kong Science Museum from tomorrow to April 7, 2002, will feature ancient astronomical instruments, chronographs, star maps and meteorites by displaying real objects, stone rubbings, replicas and models. Among the 44 sets of fascinating exhibits brought from Beijing Planetarium, Beijing Ancient Observatory and Suzhou Ancient Astronomical Chronograph Research Centre, two exhibits, the Ecliptic Armillary Sphere and the Quadrant, are classified as Chinese First Class National Treasures.

In ancient China, astronomy was a vital importance to the people, who depended very much on agricultural economy. By observing the sky, people were able to forecast seasonal changes accurately and to devise calendar to plan the agricultural activities such as sowing and reaping. Moreover, the ancient emperors called themselves "the Son of Heaven". They believed that they were sent to the Earth at God's will and thought that changes in celestial phenomena were closely linked with the fate of their reigns. Therefore, the officials responsible for astronomical affairs had extremely high status in the society.

From the oracle inscriptions of the Shang Dynasty (C. 1700-1050 B.C.) on tortoiseshells and animal bones, we know that people at that time already used sunrise and sunset to count days. By observing the syzygy of the Moon and the periodic positions of the Sun in the sky, they also learnt how to count months and years. In the Zhou Dynasty (1050-221 B.C.), Emperor Wen built an observatory for astronomical observation, solar term determination and calendar compilation.

The Twenty-eight Mansions system first emerged in the period between the early Zhou and the Han (206 B.C. - A.D.220) Dynasties. Insertion of seven intercalated months for every 19 years was also established in the compilation of calendar. In the Han and the Tang (618-907) Dynasties, people discovered that the Sun did not move at a constant pace. They then determined the solar terms according to 24 equal distances travelled by the Sun on the celestial sphere. People also defined the conjunction of the Sun and the Moon as the first day of a lunar month. By observing the variant motion of the Moon, they were able to obtain the lunar syzygy. During the Song, the Yuan and the early Ming Dynasties (960-1460), numerous sophisticated astronomical instruments were invented and long-term celestial surveys were conducted. Outstanding achievements in calendar theory, calendar calculations and astronomical documentation were thus obtained.

By the time in the early Qing Dynasty (1644-1754), eight large-scale astronomical instruments such as the ecliptic armillary sphere were constructed and astronomical books such as the Lingtai Yixiang Zhi (Catalogue of Astronomical Observatories and Instruments), Lixiang Kaocheng (Complete Studies on Astronomy and Calendar) book 1 and 2, and Yixiang Kaocheng (Complete Studies on Astronomical Instruments) book 1 and 2 were compiled.

The Ecliptic Armillary Sphere and the Quadrant, featured in the current "Ancient Chinese Astronomy" exhibition, were also constructed in Qing Dynasty. They were constructed under the supervision of the Belgian missionary Ferdinand Verbiest in the Kangxi reign (1669-1673) in the Qing Dynasty. They were two of the six astronomical instruments at the Beijing Ancient Observatory. They had been seized by the Joint Armies of the Eight Nations from Beijing in 1900 and were returned to China in 1902. Since then, these two national treasures have never been exhibited outside Beijing.

The Ecliptic Armillary Sphere is the first astronomical observation instrument that employs the ecliptic coordinate system. Since ancient Chinese astronomers paid little attention to ecliptic coordinates, they only attached an ecliptic circle to the equatorial circle of the armillary sphere. In fact, ecliptic coordinates were not directly used for measurements. This system, however, is more convenient than the equatorial one in observing the motions of the Sun and planets. The advent of the Ecliptic Armillary Sphere is therefore a remarkable breakthrough in the history of Chinese astronomy.

The Quadrant is an instrument designed for measuring a celestial body's altitude and distance from the zenith. It performs the same function as the revolvable vertical circle on the azimuthal system of the equatorial torquetum. The revolvable vertical circle is a complete circle while the quadrant is only an arc of 90(that is adequate for mensuration purpose. Therefore, the quadrant can be deemed as a simplified azimuthal system of the equatorial torquetum.

In this exhibition, visitors may have the opportunity to operate the scaled models of selective exhibits and understand the working principles behind these instruments. Moreover, the legendary stories on Chinese constellations, the Sun and the Moon will also be introduced and interpreted in the light of modern astronomy.

To coincide with the exhibition, the Science Museum has also organised a series of activities for the public including the Fun Science Experiments- "Little Astronomer", Weekend Children Programmes- "Simple Astronomy Kit-DIY" and Popular Science Lectures- "Astronomical Instruments in Ancient China", "Ancient Chinese Astronomy and Calendars" and "Astronomical Observations in Ancient China". Those who are interested in the details may browse the newsletter of Science Museum or visit the Science Museum's website at http://www.lcsd.gov.hk/hkscm/.

Moreover, a new Sky Show with the same title - "Ancient Chinese Astronomy" to be staged at the Hong Kong Space Museum from November 28, 2001 will further enhance the public's knowledge of the astronomical development in ancient China. Please visit the Museum's website http://www.lcsd.gov.hk/CE/Museum/Space for details.

The admission fee of the "Ancient Chinese Astronomy" exhibition is HK$35. On Wednesdays, admission is HK$10. Half-price concession is applicable to full-time students, people with disabilities and senior citizens aged 60 or above.

Hong Kong Science Museum is located at 2 Science Museum Road, Tsim Sha Tsui East, Kowloon. It opens from 1 pm to 9 pm on weekdays and from 10 am to 9 pm on Saturdays, Sundays and public holidays. It closes on every Tuesday (except public holidays). For enquiries, please call 2732 3232.

End/Thursday, November 15, 2001

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