Background

Eugène Michel Antoniadi was born on March 1, 1870 and grew up in what was then called the Tatavala quarter of Constantinople, now Istanbul, Turkey. His family was part of the repressed Greek community of the time, and according to travel writer E. H. Cookridge, that district of the city was actually more of a slum ghetto where the less affluent Greeks were forced to live. He had a brother Dorotheos, however, not much known about all of his siblings and relations.

Career

At the age of eighteen, using very modest instruments, Antoniadi began his long series of observations in Constantinople and on the island of Prinkipe. He published these observations, and most of his others, in Camille Flammarion’s review L’astronomie, the bulletin of the Astronomical Society of France. A frequent and diligent observer, Antoniadi was also an artist. His drawings from observation far surpass those of many other astronomers who lacked his artistic ability.

In 1893 Antoniadi was Flammarion’s guest in his private observatory at Juvisy, near Paris. Here he was able to employ a forty-two-centimeter equatorial to observe Mars, which was his chief concern. As a result of his research he was appointed director of the section on Mars of the British Astronomical Association.

In 1909 H. Deslandres, director of the observatory at Meudon, authorized him to make use of the large telescope there, which led Antoniadi to make important discoveries regarding the constitution of the surface details of Mars. This was possible because in that year the planet, in a close opposition, was in an extremely favorable position to be observed. Antoniadi’s excellent drawings of that particular opposition and of those that followed revealed that the strange network of geometrical “canals,” which some observers had thought to be man-made, are no more than an effect produced by very minute details. It was his conclusion that 70 percent of the canals are irregular dark bands, more or less continuous and scattered with small spots that vary in width and appearance; 21 percent are irregular lines of gray, diffuse spots; 9 percent are isolated and complex nuclei. Antoniadi’s drawings, reproduced in his major work, show terrain covered with sparse vegetation, volcanic soil, and vast deserts.

During the opposition of 1924 Antoniadi observed, among other things, shining protuberances on the edge of the planet, precisely on the configuration called Hellas. The highest point of these protuberances seemed to oscillate, over a period of four days, eight to twenty kilometers above the surface of the planet. By observing the apparent motion of the various details of Mars, Antoniadi also was able to confirm the period of rotation about its axis, which had been determined by Giovanni Schiaparelli.

In later life Antoniadi became interested in the history of Greek and Egyptian astronomy; the results of his studies were published in L’astronomie and in his L’astronomie égyptienne. In addition, outside the field of astronomy, he conducted important archeological studies on the basilica of Saint Sophia in Constantinople, which were published in 1907.

Achievements

• 

  Antoniadi became a highly reputed observer of Mars and at first supported the notion of Martian canals, but after using the 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 and made the first attempts to draw a map of Mercury, but his maps were flawed by his incorrect assumption that Mercury had synchronous rotation with the Sun. The first standard nomenclature for Martian albedo features (an albedo feature is a large area on the surface of a planet which shows a contrast in brightness or darkness of adjacent areas) was introduced by the International Astronomical Union when they adopted 128 names from the 1929 map of Antoniadi.
  
  Antoniadi was also a prolific writer of articles and books (the Astrophysics Data System lists nearly 230 that he authored or co-authored). The subjects included astronomy, history, and architecture. He frequently wrote articles for L'Astronomie of the Société astronomique de France, Astronomische Nachrichten, and the Monthly Notices of the Royal Astronomical Society, among others.
  
  The French government awarded him the Cross of Chevalier of the Legion of Honor, and in 1928 he was granted with the French citizenship. Antoniadi impact crater on the Moon named in his honor by the International Astronomical Union in 1970. A crater on Mars named in his honor by the International Astronomical Union in 1973. Antoniadi Dorsum wrinkle ridge on Mercury named in his honor by the International Astronomical Union in 1976.

Works

• book

  • La Planete Mercure et la Rotation des Satellites. Etude Basee sur les Resultats Obtenus Avec la Grande Lunette de l'Observatoire de Meudon

Views

Antoniadi was more than a professional astronomer; he was an astrophile.

Membership

Antoniadi was a Fellow of the Royal Astronomical Society since 1899 and was one of the founding members of the British Astronomical Association (BAA). He also became a member of the Société astronomique de France (SAF) in 1891.

Personality

Antoniadi was a rather private man. He was an excellent correspondent but didn’t go to many astronomical meetings, at least not after his marriage. One organisation wanted to send him to a convention in Leyden, but he simply replied that he was not the man for such meetings: working alone and in private was what he liked most. He preferred a small number of close friends or correspondents, and occasionally held a soirée in his Paris appartment.

Physical Characteristics: Antoniadi always dressed meticulously, perhaps more resembling an undertaker than an astronomer. He wore small round spectacles, and was in the habit of carrying an old pair with the left lens blacked out so the left eye could remain open whilst observing. We therefore can see him dressed rather formally upon the platform of the Grande Lunette in 1924 and 1925, with thinning white hair, then in his mid-fifties, but he still seems to have a commanding presence. His hat is stacked together with Baldet’s on the table, and he holds a sketch pad.

Interests

• Antoniadi had many interests and excelled in most of them; he wrote (in Greek) the definitive book on the architecture of Istanbul’s beautiful basilica, Hagia Sophia, and played chess well enough to take two games from future United States national champion Frank Marshall in 1907.

Connections

Eugène Michel Antoniadi was married to Katherine Sevastopoulos, a member of a wealthy Greek family living in Paris. The family also had roots in Constantinople, and the Antoniadi and Sevastopoulos families were well connected with merchants, bankers, even one big arms dealer and even two different European Royal families.

Brother:

Dorotheos Antoniadi

Wife:

Katherine Sevastopoulos

She was a member of a wealthy Greek family living in Paris.

Acquaintance:

Edward Emerson Barnard

Antoniadi got the chance to meet many famous astronomers whilst at Juvisy. In particular, he met Edward Emerson Barnard and Percival Lowell.

associate:

Percival Lowell

Friend:

Abbé Theophile Moreux

Théophile Moreux (20 November 1867 – 13 July 1954) was a French astronomer and meteorologist.

References

• Dictionary of Scientific Biography
• Journal Of The British Astronomical Association