Louis Flecheux was a French astronomer and mathematician.
Flecheux moved to Paris, living in Montmartre from at least 1775 until his death in 1793, where he constructed a celestial observatory for making observations from the heights of the hill.
In 1780, He sent his first work to the Academy of Sciences, Planétaire mobile ou planisphère nouveau, which explained an ingenius machine created by Flecheux. Its purpose was to facilitate the study of the movement of the stars and to trace a convenient route for celestial exploration. This was followed shortly thereafter by his Carte générale dela Terre appliquée à l'astronomie, a curious map intended to illustrate celestial phenomenon as they transited the earth.
Four years later, he published his Loxocosme ou démonstrateur du mouvement annuel tropique et diurne de la Terre autour du Soleil, et causes des phénomènes des saisons, de l'inégalité des jours, du lever et du coucher du Soleil par toute la Terre, du cours de la Lune et des planètes, etc., avec des réflexions sur le système de Copernic. In it, he describes an ingenious invention, a machine supposedly remarkable for its simplicity and precision. The machine was demonstrated at the College de France and later for the Queen of England, and various scientists from Denmark, Germany, and Italy.
Flécheux was also the inventor of a quarter circle to take the height of the sun, draw meridians, and adjust watches and clocks.
In 1793, during the fanaticism that accompanied the French Revolution, Flecheux's nocturnal visits to his observatory made him suspect of witchcraft; he was put on the list of suspect individuals. He fled Montmartre, distressed and disgusted; he organized his affairs and then burned himself to death.