Making a list of the greatest or brightest comets of all time is a difficult task. With visual brightness aside, some of these comets would have become more popular than others based on a number of factors. This could include their position in the sky, how long their tail became and how long they stayed visible to the naked eye. Therefore, this list is simply in order of apparent magnitude with the brightest at the top. The other difficulty with more historical comets is predicting their brightness. Apparent magnitudes were not used or recorded in comets before the 20th century, so there is plenty of approximation involved. The earlier you go back in time, the more primitive the records are. In ancient times, comets were referred to as gods without records of their position or how long they lasted. From around 1000 BC, more scientific views began to develop around comets and more notice was made of movements.
The list below has been collated with the help of data from the International Comet Quarterly (ICQ) featuring the brightest comets since 1935.
The brightest comets since 1900
| Designation | Name | Apparent Magnitude |
|---|---|---|
| C/1965 S1 | Comet IkeyaSeki | -10 |
| C/1910 A1 | Great Comet of 1910 | -7 |
| C/1927 X1 | Comet Skjellerup-Maristanny | -6 |
| C/2006 P1 | Comet McNaught | -5.5 |
| C/1975 V1 | Comet West | -3 |
| C/1947 X1 | Southern Comet | -3 |
| C/1948 V1 | Eclipse Comet | -1 |
| C/1995 O1 | Comet Hale-Bopp | -0.8 |
| C/1956 R1 | Comet Arend-Roland | -0.5 |
| C/2002 V1 | Comet NEAT | -0.5 |
| C/1996 B2 | Comet Hyakutake | 0 |
| C/1969 Y1 | Comet Bennett | 0 |
| C/1973 E1 | Comet Kohoutek | 0 |
| C/1962 C1 | Comet Seki-Lines | 0 |
| C/1998 J1 | Comet SOHO | 0.5 |
| C/1957 P1 | Comet Mrkos | 1 |
| C/1998 J1 | Comet White-Ortiz-Bolelli | 1 |
| C/1983 H1 | Comet IRAS-Araki-Alcock | 1.7 |
| C/1941 B2 | Comet de Kock-Paraskevopoulos | 2 |
| C/2002 T7 | Comet LINEAR | 2.2 |
| C/1982 U1 | Halley's Comet | 2.4 |
| 17P | Comet Holmes | 2.4 |
| C/2000 WM_1 | Comet LINEAR | 2.5 |
| C/1964 N1 | Comet Ikeya | 2.7 |
| C/2001 Q4 | Comet NEAT | 2.8 |
| C/1989 W1 | Comet Aarseth-Brewington | 2.8 |
| C/1962 A1 | Comet Ikeya | 2.8 |
| 153P C/2002 C1 | Comet Ikeya-Zhang | 2.9 |
| C/2001 A2 | Comet LINEAR | 3 |
| C/1936 K1 | Comet Peltier | 3.3 |
| C/2004 F4 | Comet Bradfield | 3.3 |
| C/2004 Q2 | Comet Machholz | 3.5 |
| C/1942 X1 | Comet Whipple-Fedtke-Tevzadze | 3.5 |
| C/1940 R2 | Comet Cunningham | 3.5 |
| C/1939 H1 | Comet Jurlof-Achmarof-Hassel | 3.5 |
| C/1959 Y1 | Comet Burnham | 3.5 |
| C/1969 T1 | Comet Tago-Sato-Kosaka | 3.5 |
| C/1980 Y1 | Comet Bradfield | 3.5 |
| C/1961 O1 | Comet Wilson-Hubbard | 3.5 |
| C/1955 L1 | Comet Mrkos | 3.5 |
| C/1990 K1 | Comet Levy | 3.6 |
| C/1975 N1 | Comet Kobayashi-Berger-Milon | 3.7 |
| C/1974 C1 | Comet Bradfield | 3.9 |
| C/1937 N1 | Comet Finsler | 3.9 |
Below is a list of brighter comets recorded before 20th century. As said before, the magnitude figures are approximated but many of these great comets are well documented and are definitely worth the mention.
Bright comets before the 20th century
| Designation | Name | Apparent Magnitude |
|---|---|---|
| X/1106 C1 | Great Comet of 1106 | -? |
| C/1882 R1 | Great Comet of 1882 | -15 |
| C/1843 D1 | Great Comet of 1843 | -? |
| C/1680 V1 | Great Comet of 1680 | -? |
| C/1743 X1 | Great Comet of 1744 | -7 |