Édouard Stephan

He was born in Sainte Pezenne (today one of the districts of the town of Niort) and attended the Ecole Normale Superieure, and graduated at the top of his class in 1862.

[2] In the early part of his career there, he had limited opportunities to do observations because he was preoccupied with improving the observatory.

[1] Between 1870 and 1875, Stephan systematically studied nebulae, precisely recording their positions and discovering many new ones.

[1] His goal was to enable the exact measurement of stellar proper motions by creating a reference system of fixed objects.

[1] In 1873, Stephan was the first person to attempt to measure the angular diameter of a star using interferometry, converting the 80 cm telescope at Marseille Observatory into an interferometer.