Encke's comet

Encke's Comet was the second comet after Halley's whose cometary orbit had been worked out. This one was the first short-period comet, with a period of 3.3 years, which challenged previous celestial calculations.
 Johann Franz Encke Germany 1818 Encke's comet

Encke's Comet was the second comet after Halley's whose cometary orbit had been worked out. This one was the first short-period comet, with a period of 3.3 years, which challenged previous celestial calculations.