Françoise Launay’s research while affiliated with Paris Observatory and other places

‘Modern astronomy’ was introduced to Siam (present-day Thailand) when the Belgian Jesuit missionary-astronomer Father Antoine Thomas carried out astronomical observations in 1681 and 1682 in order to determine the latitude and longitude of Ayutthaya. Three years later a contingent of French Jesuit missionary astronomers observed a total lunar eclipse from Lop Buri, which marked the start of an intensive two-and-a-half year period of observational activity at Lop Buri under the sponsorship of King Narai. This ended only with King Narai’s premature death in July 1688, and Western missionary-astronomers were then expelled from Siam. This situation only changed markedly nearly two hundred years later when another Royal supporter of astronomy, King Rama IV, invited French astronomers to observe the total solar eclipse of 18 August 1868 from Siam, and his son, King Rama V, hosted British astronomers during the 6 April 1875 total solar eclipse. Thailand’s romance with solar astronomy continued during the 9 May 1929 solar eclipse when King Rama VII visited British and German astronomers based near Siam’s southern border, and in the 1930s Thailand’s first astronomy course was taught at Chulalongkorn University. This chapter provides biographical information about Antoine Thomas, before examining the astronomical observations that he made in 1681 and 1682, and recent attempts to pinpoint his observing site. It then briefly sketches the development of ‘modern astronomy’ in Siam during the remainder of the seventeenth century, and in the nineteenth century, leading up to the emergence of professional astronomy during the twentieth century, and the formation of the National Astronomical Research Institute of Thailand in 2009.

On 18 February 1679 Paris Observatory astronomer Jean Dominique Cassini presented a new map of the Moon to the Academy of Sciences in Paris, and this then became the standard reference work for French astronomers who carried out selenographical observations. Among these was a contingent of Jesuit missionary-astronomers who sailed from Brest on 3 March 1685, bound for China. En route they were forced to spend some months in Siam (present-day Thailand) and used the map when they observed the lunar eclipse of 11 December 1685. In this paper we examine the creation of the 1679 Moon map and its use by the French Jesuit missionary-astronomers in Siam in 1685.

On 18 February 1679 Paris Observatory astronomer Jean Dominique Cassini presented a new map of the Moon to the Academy of Sciences in Paris, and this then became the standard reference work for French astronomers who carried out selenographical observations. Among these was a contingent of Jesuit missionary-astronomers who sailed from Brest on 3 March 1685, bound for China. En route they were forced to spend some months in Siam (present-day Thailand) and used the map when they observed the lunar eclipse of 11 December 1685. In this paper we examine the creation of the 1679 Moon map and its use by the French Jesuit missionary-astronomers in Siam in 1685.

Everybody knows that D'Alembert was a foundling brought up by a wet‐nurse he was much attached to, and that he was very grateful to the director of the boarding school where he spent eight years before going to Mazarin College. However neither the wife of the glazier Rousseau nor the schoolmaster Berée had been correctly identified since D'Alembert's death. The places where they lived had not been precisely located in Paris. Moreover the man who provided D'Alembert with a means of existence all of his life has always been considered without any proof, as more than the guardian he actually was, while the name “Jean Baptiste Louis d'Aremberg” that Jean Le Rond had believed to be his name for eighteen years has never been really questioned. Thanks to quite a number of manuscripts we have been able to find in national and local archives or libraries over several years, the biography of D'Alembert is now more precisely documented, the results of our investigation include a well‐argued hypothesis regarding D'Alembert's biological father.