PERROTIN
Henri, Joseph Anastase
1845-1904
Astronomer, first Director of Nice Observatory
Meanwhile, he turned to celestial mechanics.
Following the method used by Le Verrier for the big planets, particularly
the theories of Jupiter and Saturn, he started developing the first
precise theory of the asteroid Vesta, which gave the matter of his thesis,
in 1879. In this work he presented results relative to the perturbing function
that was used to verify recent theories of Vesta.
In 1880, he was appointed as director of the
newly founded private observatory at Nice to install it. He was recommended
by the Bureau des Longitudes, to the sponsor Bischoffsheim, and for more
than twenty years, until his death, he devoted himself to set up
a well equipped observatory, and to supervise its growth. In 1882, the Académie
des Sciences designed him as the leader of the expedition to observe the
transit of Venus, in Patagonia, at Carmen de Patagonès, aside of
the Rio Négro.
Upon his return at Nice, the most active part of
Perrotin's career began. He gave an important impulse to all work,
wether they concern the constructions of instruments, or scientific researches
and he greatly contributed to the fame of the establishment. He supervised
the setting of instruments among them, the seventy-six-centimeter refractor
(1886), which was one of the world's largest at that time. He used
it to carry out observations of double stars, and of large and small
planets.
His studies on planets were remarkable, especially those
on Mars and Venus. He tried to verify Schiaparelli's discoveries, on " canals
of Mars ", and on rotation period of Venus, in 225 days. On both sides
he confirmed the Milan's astronomer results, but later the history showed
they were wrong for Mars and insufficient for Venus. However his detailed
observations of the Martian surface were interesting, and his drawings
of Venus surface (1890)shows that he had noticed, seventy years before,
by visual means, the now famous Y and Psi shaped markings, recognized to
day in the Venusian clouds. He organized also meteorological and magnetic
observations.
Apart from his astronomical work, in
the field of physics, he added another determination on the velocity of
light. He made a series of very accurate observations to improve this measurement,
with the Fizeau's slotted-wheel method applied to beams sent between
the Mont Gros and the Mont Vinaigre, the highest point of the massif
of Estérel, distant of 46 km. The 299.880 km / second value, obtained
in 1902, using this trajectory, was regarded as the best until the estimation
of Michelson(1926).
Perrotin founded the Annales de l'Observatoire
de Nice in 1887, he managed the publication of the first 10 volumes, and
wrote several of them.
Twice awarded for the Lalande price, by the Académie des
Sciences, in 1875, and in 1884,
Corresponding member of the Académie des Sciences (1892).
Corresponding member of the Bureau des Longitudes(1894).
Perrotin's skeches of the surface of Venus observed
from May 23rd to Septembrer 27, 189
Raymonde Barthalot
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References:
E. STEPHAN, Notice, Annales de l’Observatoire de Nice, t.8, 1904.
J. R. LEVY, Henri Perrotin, Dictionary of Scientific
Biography, 14 volumes, ed. Charles Scribner’s sons, New-York, 1970-76.
W. TOBIN, Toothed wheels and rotating mirrors: Parisian astronomy
and mid-nineteenth century experimental measurements of the speed of
light, in Vistas in Astronomy, 36, 1993, (253-294).
