Jean Picard

Jean Picard
Jean Picard was born July 21 in 1620 in La Fleche, Anjou. About the biography of astronomer almost nothing is known. Maybe in his younger years, he graduated from the seminary and was ordained. But fully preserved information about its research.

Picard he perfected the modern tools and methods for observing celestial bodies, improve their accuracy. One of his achievements was the micrometer with movable threads. This tool is possible to measure the angular diameters of the sun, moon and planets.

He first used the peculiar sight of the telescope in focus with crossed threads in the goniometer. This allowed him to very high precision to measure the length of a meridian and, as a consequence, to calculate the radius of the Earth.

Drawings astronomical instruments used by the Picard Picard calculated length of one degree of the meridian of 30 meters is different from the one they use now. It Picard first expressed the idea that the Earth is not spherical, but slightly flattened at the poles.

Picard has collaborated with many scientists, including the famous Huygens and even his main rival Giovanni Cassini, with whom he was in Paris on observations of the planet Mars to determine the solar parallax. Studies of the stars leads him far beyond real estate, he has devoted most of the time.

In particular, he studied the phenomenon of the aberration of light (that is, the apparent displacement of the observed object due to the properties of the light and the movement of the observer), and the observed phenomena of phosphorescence of various substances. His research led to the development of further spectrometry.

In the 1670s Picard participated in the excavation of the observatory of Tycho Brahe (Uraniborg) in Denmark, founded the Astronomical Yearbook Ā«Connaissance des tempsĀ», was compiled and edited his first 4 volumes. He was a member of the Paris Academy of Sciences.

Died Jean Picard 12 July in 1682 in Paris.

In honor of the scientist called the orbital observatory, observing the sun.