Encke, Johann Franz, a celebrated German astronomer, born at Hamburg; determined the sun's distance, and the orbit of the comet of 1680; calculated the time of the revolution of the comet which now bears his name, and which appeared in 1818; determined also the distance of the sun by the two transits of Venus in 1761 and 1769 (1791‒1865).
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Encina * Encyclical Letter