The postal authorities of Denmark and China have jointly issued a set of stamps commemorating famous astronomers from both countries, and a launch ceremony was held in Copenhagen on January 4.

Photo taken on Jan. 4, 2012 shows the stamps called Ancient Astronomical Instruments during the launching ceremony at the Tycho Brahe Planetarium in Copenhagen, Denmark. The series of two stamps, which were jointly issued by postal authorities of Denmark and China, feature the Abridged Armilla of the 13th century Chinese astronomer Guo Shoujing, and the armillary sphere of his 16th century Danish counterpart Tycho Brahe. [Xinhua/Wu Bo]

The series of two stamps, called Ancient Astronomical Instruments, feature the Abridged Armilla of the 13th century Chinese astronomer Guo Shoujing, and the armillary sphere of his 16th century Danish counterpart Tycho Brahe.

"It was important for both postal authorities to find a cultural theme that we could collaborate on," said Lene Reipuert, Manager of Stamps at Post Danmark.

"We came to agree on astronomy because we have this history of astronomy, in Denmark with Tycho Brahe, and with the tradition of astronomy going much further back in China," she said.

According to Post Denmark, it was the first time the two countries' postal authorities collaborated on design and issue of such philatelic products.

People buy the stamps called Ancient Astronomical Instruments during the launching ceremony at the Tycho Brahe Planetarium in Copenhagen, Denmark, on Jan. 4, 2012. The series of two stamps, which were jointly issued by postal authorities of Denmark and China, feature the Abridged Armilla of the 13th century Chinese astronomer Guo Shoujing, and the armillary sphere of his 16th century Danish counterpart Tycho Brahe. [Xinhua/Wu Bo]