How many comets were discovered by Jean-Louis Pons?

Version June 26, 2026

Prompted by several Wikipedia and other articles which claim that Jean-Louis Pons discovered 37 comets I set out to settle this question. Of course, it depends heavily on the definition of the term DISCOVERY, and even today it is a kind of debate if an independent discovery can still be a genuine discovery.

The number of 37 comet discoveries for Jean-Louis Pons comes from the 1960 paper by Elizabeth Roemer which says that he discovered "at least 37 comets" but without giving a list.

My following tables give his

  • named discoveries
  • discoveries which were renamed later
  • unconfirmed discoveries
  • independent but not named discoveries

    The first table below shows the genuine discoveries while the second table shows the independent and unconfirmed discoveries, which are not credited.

    Based on the tables below we can state:

  • Pons has made 32 genuine credited comet discoveries of 31 individual comets because one was a rediscovery.
  • Of these, 4 comets (including the rediscovery, no. 19) were later named after other individuals.
  • There are 27 individual comets that bear his name.
  • There is one unconfirmed comet discovery (no. X2).
  • There are 6 known independent discoveries, which were not credited.
  • This makes him involved with at least 39 comet discoveries.

    • The reason why there is a difference between Elizabeth Roemer's paper which gives at least 37 comets and my number of 39 comets is probably the fact that the formerly unconfirmed comet C/1808 R1 was not not widely known and omitted in many Cometographies. Only after research by G. W. Kronk and myself in 2023 we were able to find letters containing positions for this obscure object, allowing the calculation of an orbit and its subsequent formal numbering and naming. Also, Roemer might have left out the other unconfirmed comet.

    Table 1: Genuine and credited comet discoveries by Jean-Louis Pons


    No. Designation Type Notes
    1
    C/1801 N1 (Pons)
    genuine
    First comet discovery of the 19th century.
    2
    C/1802 Q1 (Pons)
    genuine
    3
    C/1804 E1 (Pons)
    genuine
    4
    2P/1805 U1 (Encke)
    genuine
    Later named after Johann Franz Encke, who noted the periodicity and linked several apparitions.
    5
    3D/1805 V1 (Biela)
    genuine
    First seen in 1772. Later named after Wilhelm von Biela, who discovered it in 1826 and noted the periodicity and linked the apparitions.
    6
    C/1806 V1 (Pons)
    genuine
    7
    26P/1808 C1 (Grigg-Skjellerup)
    genuine
    Discovered in 1902 by John Grigg and 1922 by John Francis Skjellerup, linked to Pons' comet in 1987 by Ľubor Kresák.
    8
    C/1808 F1 (Pons)
    genuine
    9
    C/1808 M1 (Pons)
    genuine
    10
    C/1808 R1 (Pons)
    genuine
    Confirmed in 2023 by G. W. Kronk and M. Meyer, see "Catalog of Unconfirmed Comets - V1" and CBET 5258.
    11
    C/1810 Q1 (Pons)
    genuine
    12
    C/1811 W1 (Pons)
    genuine
    13
    12P/1812 O1 (Pons-Brooks)
    genuine
    14
    C/1813 C1 (Pons)
    genuine
    15
    C/1813 G1 (Pons)
    genuine
    16
    C/1816 B1 (Pons)
    genuine
    17
    C/1817 Y1 (Pons)
    genuine
    18
    27P/1818 D1 (Crommelin)
    genuine
    Formerly also known as Pons-Coggia-Winnecke-Forbes, later named after Andrew Claude de la Cherois Crommelin, who linked the apparitions.
    19
    2P/1818 W1 (Encke)
    genuine
    Identical to no. 4, second discovery (so it is formally rather a recovery) of this comet by Pons.
    20
    C/1818 W2 (Pons)
    genuine
    21
    7P/1819 L1 (Pons-Winnecke)
    genuine
    22
    C/1821 B1 (Nicollet-Pons)
    genuine
    23
    C/1822 K1 (Pons)
    genuine
    24
    C/1822 N1 (Pons)
    genuine
    25
    C/1825 N1 (Pons)
    genuine
    26
    C/1825 P1 (Pons)
    genuine
    27
    C/1825 V1 (Pons)
    genuine
    28
    C/1826 P1 (Pons)
    genuine
    29
    C/1826 U1 (Pons)
    genuine
    30
    C/1826 Y1 (Pons)
    genuine
    31
    273P/1827 M1 (Pons-Gambart)
    genuine
    32
    C/1827 P1 (Pons)
    genuine


    Table 2: Independent and unconfirmed comet discoveries by Jean-Louis Pons



    No. Designation Type Notes
    X1
    C/1807 R1 (Great Comet)
    independent
    First known report of 1807 September 9 by C. Giovanni, Sicily, Italy. Pons found it on September 21.
    X2
    X/1808 N1
    unconfirmed
    Seen only on 1808 July 4 and 6.
    X3
    C/1811 F1 (Great Comet)
    independent
    Discovered on 1811 March 25 by Pierre Gilles Antoine Honoré Joseph Flaugergues, Viviers, France. Independently found by Pons on April 11.
    X4
    289P/1819 W1 (Blanpain)
    independent
    Discovered on 1819 November 28 by Jean-Jacques Blanpain, Marseille, France. Independently found by Pons on December 5.
    X5
    C/1822 J1 (Gambart)
    independent
    Discovered on 1822 May 12, by Jean-Félix Adolphe Gambart, Marseille, France. Idenpendently found by Pons on May 14.
    X6
    C/1823 Y1 (Great Comet)
    independent
    Discovered on 1823 December 29, by Nell de Bréauté, Dieppe, France. Independently found by Pons on December 30.
    X7
    C/1824 O1 (Scheithauer)
    independent
    Discovered on 1824 July 23, by Christian Friedrich Scheithauer, Chemnitz, Germany. Independently found by Pons on July 24.

    Last update: June 29, 2026

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