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
Naming of comets the past, when multiple comets were discovered by the same individual, group of individuals, or team, the comets' names were distinguished by adding a numeral to the discoverers' names (but only for periodic comets); thus Comets Shoemaker–Levy 1 to 9 (discovered by Carolyn Shoemaker, Eugene Shoemaker & David Levy). Today, the large numbers of comets discovered by some instruments makes this system impractical, and no attempt is made to ensure that each comet is given a unique name. Instead, the comets' systematic designations are used to avoid confusion. Until 1994, comets were first given a provisional designation consisting of the