Louis Thollon

[1] Beginning in 1881, Thollon joined the staff of the new Nice Observatory where he undertook a long-term observation program of the Sun using a spectroscope of his own design.

[4] The same year he traveled to Portugal to watch the Venus transit, but was met with disappointment due to poor weather.

[5] He was awarded the Prix Lalande in 1885 for his large map of the solar system, which was not published until after his death in 1890.

[6] During the 1886 Mars opposition, he assisted the observatory director, Henri Perrotin, in observing the planet with a 15 in (38 cm) reflecting telescope.

Both men reported that they spotted canali on the surface of the planet, apparently confirming the 1877 discovery of these features by Italian astronomer Giovanni Schiaparelli.