Antoniadi was born in
Istanbul (
Constantinople) but spent most of his adult life in
France after being invited there by
Camille Flammarion. He became a Fellow of the
Royal Astronomical Society on 10 February 1899, and in 1890 he became one of the founding members of the
British Astronomical Association (BAA). In 1892, he joined the BAA's Mars Section and became that section's Director in 1896. He became a member of the
Société astronomique de France (SAF) in 1891. Flammarion hired Antoniadi to work as an assistant astronomer in
his private observatory in
Juvisy-sur-Orge in 1893. Antoniadi worked there for nine years. In 1902, he resigned from both the Juvisy observatory and from SAF. Antoniadi rejoined SAF in 1909. That same year,
Henri Deslandres, Director of the
Meudon Observeratory, provided him with access to the
Grande Lunette (83-cm Great Refractor) He became a highly reputed observer of
Mars, and at first supported the notion of
Martian canals, but after using the 83 centimeter
telescope at
Meudon Observatory during the 1909
opposition of Mars, he came to the conclusion that canals were an
optical illusion. He also observed
Venus and
Mercury. He made the first
map of Mercury, but his maps were flawed by his incorrect assumption that Mercury had
synchronous rotation with the
Sun. He is also famed for creating the
Antoniadi scale of seeing, which is commonly used by
amateur astronomers. He was also a strong
chess player. His best result was equal first with
Frank Marshall in a tournament in
Paris in 1907, a point ahead of
Savielly Tartakower. He died in
Paris, France, aged 73. == Name ==