First of all, Henri Perrotin was the first director of this magnificent realization. By his undeniable qualities of managing, and his personal works he contributed very much to the fame of the Establishment. He knew how to choose a skillful staff, and to attract high-level scholars.
Perrotin made notable studies on planets: his observations of the March surface contributed to make progress to the cartography of the planet; his researches on Venus rotation attracted attention, even though the data were badly missing at that time to let him to do a correct measure of its rotation speed ; and he perceived new details in the Saturn rings. As concerns the small planets, he made the Vesta's theory.
Perrotin also studied nebulae double stars that were so closed to one another that they were unobservable any where else in Europe, meteorology and Earth magnetism.
He realized with Alfred Cornu, famous experiments of the measure of the speed of light between the Mont Gros and La Gaude (12km) and carried on them with his assistants Prim and Simonin, between the Mont Gros and the Mont Vinaigre (Estérel) (46km), improving his determination, with a precision that will be superseded only twenty years later. Finally, he laid the foundations of the Annals of Nice Observatory.
collimator
rotating
toothed wheel observer
Louis Thollon, who had begun his observations at the Mont Gros even before the Observatory was built, dedicated the major part of his activity to the Sun, and measured its rotation, comparing the Doppler effect of the solar lines with fixed telluric lines. He studied the movements in the sun protuberances, their helical complexity, and he brought to light speeds of the order of 500km /sec-1.
Of his systematic study of the solar spectrum, Thollon made a large atlas published after his death, in 1890. The spectra extended over 3448 lines, the double of Angström's classical atlas , and a third part of these lines were clearly identified by Thollon as being of telluric origin. The whole was of a remarkable precision for its time and it was the most important document on the solar spectrum ever realized with the spectroscope. A better result will be obtained only by spectrography.
Alexandre Schaumasse and Michel Giacobini discovered a large number of comets. From 1896 till 1907, Giacobini discovered 12 comets among which two are periodical: comets Tuttle-Giacobini and Giacobini-Zinner.
Auguste Charlois was called " the ferret of small planets ", because he discovered hundred of asteroids. His career was brutally interrupted in 46 years old, when he was murdered by his brother-in-law. This event was in the local news and threw the scientific world into consternation.
Charles Nordmann was one of the precursors of radio astronomy. He came at the Observatory when he was very young and he there prepared a thesis and published original articles on an experience which he undertook, in 1901, on the slopes of the Mont Blanc (French Alps) in order to detect the Hertzian radiation of the Sun . He was not able to prove it, because he worked at a time of minimum activity of the Sun and at too long wavelengths taht are essentially blocked by the ionosphere. He carried on his career at the Paris Observatory, by making remarked photometric studies of the variable stars, and theoretical researches on the intrinsic state of the Sun.
In 1892, the coudé equatorial, the principle of which was due to Loewy was put in service and indicated the beginning of the photographic observations for comets and planets researches.
The next year, at the request of Perrotin, Bischoffsheim settled an annex station of observation for the study of big planets and particularly the rotation of Venus, at the top of one of the summits of the Maritime Alps, the Mont Mounier (2740m), above Valberg, in the district of Puget-Théniers where he just hapenned to be elected as a member of parliament. Meteorological observations were also made there, but the station was abandoned in 1910.
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