In May last year we had 16 days in China – most of that time was spent in Nanjing. It was hot and humid and disgustingly smoggy – apparently it gets REALLY REALLY hot & humid and REALLY disgustingly smoggy in July & August!! Nanjing is one of the three hottest cities in China with temperatures regularly over 105 F in summer – but then it drops to 19F in winter – so quite a range.
So … because the astro-dweeb was there working on a project with a Purple Mountain scientist he went to work in the observatory offices each morning with our host Jianghui, and I got to roam the city on my own & loved every minute. Then, on many afternoons Jianghui took us to places he thought were interesting or must-see in Nanjing. One such outing was a trip up Purple Mountain. Purple Mountain is China's first modern observatory – started in 1929, completed 1934 – and one of only 3 in China. It is considered the "cradle of the modern astronomy in China'.
There is a cable car which goes to the top of the mountain but I have a fear of cable cars, made in China, swinging free of their wire and hurtling down some mountainous gully – so I chose to walk up. It only took about 25 minutes to walk to the top but it was grueling in the heat and smog!
Purple Mountain is about 870 feet high and on a clear day you would be able to see Nanjing. I'm not sure when they last had a clear day!
There is a museum with astronomical displays which have descriptions in Chinese - Jianghui translated them for us and pointed out what he thought were the more important things – like the meteorite that Chairman Mao had touched in the 1960's! Many of these instruments and artifacts are actually replicas as the originals were stolen by the British, French, Germans, Americans and later the Japanese.
This is an Armillary Sphere, designed by Zhang Heng in the Eastern Han Dynasty (25-220), and used to locate celestial bodies and define their movements. It is an impressive work of art. Its four poles are engraved with entwining dragons and the four sides of the base are cast with flowers and animals. The bronze one kept here was made in 1437 during the Ming Dynasty (1368-1644). Using an instrument like this, China was the first to determine that there are 365.25 days in a year.
This is a Celestial Globe – Invented by Zhang Heng, an astronomer in the Eastern Han Dynasty (25 A.D.-220 A.D.). The one displayed here was made during the Qing Dynasty (1644- 1911). Measuring one meter in diameter, it is inlaid with 1449 stars, the ecliptic and the equator. Celestial globes were used to represent the stars and constellations of the night sky and record their positions with respect to each other and a co-ordinate system.
Nowadays only Solar Studies research is performed on the Solar Telescope at Purple Mountain as the air quality is bad and there is light pollution and radio noise from Nanjing. There are 4 remote observing stations under the auspices of Purple Mountain: Delingha, Qingdao, Ganyu and the Xuyi station where we spent 3 days.