Astronomical naming conventions order of their discovery. Thus Bennett's comet has the systematic designation C/1969 Y1. Halley's Comet, the first comet to be identified as periodic, has the systematic name 1P/1682 Q1. Comet Hale–Bopp's systematic name is C/1995 O1. The famous Comet Shoemaker–Levy 9 was the ninth periodic comet jointly discovered by Carolyn Shoemaker, Eugene Shoemaker, and David Levy (the Shoemaker–Levy team has also discovered four non-periodic comets interspersed with the periodic ones), but its systematic name is D/1993 F2 (it was discovered in 1993 and the prefix "D/" is applied, because it was observed to crash into Jupiter). Some comets were first
Rings of Saturn has been attributed to a perturbation caused by impact of material from Comet Shoemaker-Levy 9 in 1994. The C Ring is a wide but faint ring located inward of the B Ring. It was discovered in 1850 by William and George Bond, though William R. Dawes and Johann Galle also saw it independently. William Lassell termed it the "Crepe Ring" because it seemed to be composed of darker material than the brighter A and B Rings. Its vertical thickness is estimated at 5 m its mass at around 1.1 kg, and its optical depth varies from 0.05 to 0.12. That