Johan Oskar Backlund

Johan Oskar Backlund


Date of Birth
April 28, 1846
Date of Death
August 29, 1916

Oskar Backlund was born in Sweden and educated at the University of Uppsala. He spent his entire career in the Russian empire, at the Dorpat (now Tartu, Estonia) Observatory, Pulkovo Observatory, and the Imperial Academy of Sciences in Petrograd. He was director of Russia’s national observatory at Pulkovo from 1895 to 1916. Most of his research was devoted to attempting to compute the difficult orbit of Comet Encke. He employed large staffs, including many women, and recomputed all planetary perturbations, publishing six volumes on the perturbations of the comet’s orbit due to the gravitational effects of Mercury, Venus, Earth, Mars, Jupiter, and Saturn from 1819 to 1891. He used the comet to estimate the masses of Mercury and Venus. He eventually concluded that the comet’s motion was affected by nongravitational forces, such as resistance by an interplanetary medium and an unknown effect that coincided with sunspot maxima. He also measured variations in latitude caused by the wobble of the earth’s axis. Note: Two of his great grandsons have persuaded me to list his first name as Johan, but some documents, including the Dictionary of Scientific Biography, list it as Jöns. In Russia his name was written Oskar Andreevich Baklund. All agree that he was known as Oskar.

Presentation of Bruce medal

McAdie, Alexander, PASP 26, 15-18 (1914).

Other awards

Royal Astronomical Society, Gold medal, 1909, presented by H.F. Newall, MNRAS 69, 324-331 (1909).

Biographical materials

Dieke, Sally H., Dictionary of Scientific Biography 1, 371-72.
Tenn, Joseph S., “Oskar Backlund: The Eleventh Bruce Medalist,” Mercury 20, 6, 175 (1991).


Anonymous, Bulletin de l’Observatoire Central Nicolas à Poulkovo 7, 155-56 (1916) [in French].
B[aker], H.F., MNRAS 77, 310-14 (1917).
K[obold, Hermann Albert], Astr. Nach. 203, 235 (1917) [in German].
Turner, H.H. Proc. Royal Soc. 94, xx-xxiv (1918).
Anonymous, Observatory 40, 128-31 (1917).

Named after him

Lunar crater Backlund
Minor Planet #856 Backlunda


Papers, etc.

Backlund’s papers are in the Archives of the Academy of Sciences, St. Petersburg.

Other References: Historical

Search ADS for works about Backlund

Backlund, Oskar, “The Development of Celestial Mechanics During the Nineteenth Century,” in Howard J. Rogers, ed., Congress of Arts and Science Universal Exposition, Saint Louis,1904, vol IV (Houghton, Mifflin, Boston, 1906), pp. 387-95.

Batten, Allan H., Resolute and Undertaking Characters: the Lives of Wilhelm and Otto Struve (D. Reidel, 1988).

Dadaev, Aleksandr Nikolaevich, Pulkovo Observatory: an Essay on its History and Scientific Activity (National Technical Information Service, NASA TM-75083, 1978).

Krisciunas, Kevin, Astronomical Centers of the World (Cambridge Univ. Press, Cambridge, UK, 1988).

Krisciunas, Kevin, “A Short History of Pulkovo Observatory,” Vistas in Astronomy 22 (pt. 1), 27-37 (1978).

Krisciunas, Kevin, “The End of Pulkovo Observatory’s Reign as the ‘Astronomical Capital of the World’” QJRAS 25 (3), 301-305 (1984).

Mikhailov, Aleksandr A., “Pulkovo Observatory,” in Astrophysics and Twentieth-century Astronomy to 1950, ed. O. Gingerich (Cambridge Univ. Press, Cambridge, UK, 1984), p. 119-122.

Struve, Otto, “O. Backlund. Untersuchungen über die Bewegung des Enckeschen Cometen 1871-1881,” Bulletin de l’Académie Impériale des sciences de St.-Pétersbourg 29, 157-67 (1883) [in French! 4.3 MB].

Yeomans, Donald K., Comets: a Chronological History of Observation, Science, Myth, and Folklore (Wiley, NY, 1991).


Other References: Scientific

Search ADS for works by Backlund

Backlund, O., “Elements and Ephemeris of Encke’s Comet,” Observatory 4, 217, 246, 278, 310 (1881).

Backlund, O., “Mémoires et observations. Sur la masse de la planète mercure et sur l’accélération du mouvement moyen de la comète d’Encke,” Bulletin Astronomique 11, 473-85 (1894).

Backlund, O., “Encke’s Comet, 1895-1908,” MNRAS 70, 429-42 (1910).

Backlund, O., “Über die Veränderung der mittleren Bewegung des Enckeschen Kometen 1894-1908,” Astronomische Nachrichten 184, 89-92 (1910).

Backlund, O., “On Chandler’s Period in the Latitude Variation,” MNRAS 77, 2-6 (1916).

Makorev, S. G. & N. A. Bokhan, “The Motion of Comet Encke-Backlund during 1898-1911 and a New Determination of the Mass of Mercury,” Soviet Physics-Doklady 5, 923-925 (1961).