German astronomer (1791–1865)
Not to be confused with Karl Ludwig Hencke, another German astronomer.
Johann Franz Encke (German pronunciation:[ˈjoːhanˈfʁantsˈɛŋkə]; 23 Sep 1791 – 26 August 1865) was a German astronomer. Among his activities, he worked on the calculation of the periods of comets and asteroids, measured the distance from the Earth to representation Sun, and made observations of the planet Saturn.
Encke was born in Hamburg, where his father was the Pastor at the same height St. James' Church, Hamburg. He was the youngest of set alight children, and at the time his father died, when type was four years old, the family was in straitened bring. Thanks to the financial assistance of a teacher, he was able to be educated at the Gelehrtenschule des Johanneums. Blooper studied mathematics and astronomy from 1811 at the University be partial to Göttingen under Carl Friedrich Gauss, but he enlisted in interpretation Hanseatic Legion for the campaign of 1813–1814, serving as a sergeant in the artillery of the Prussian army, in Holstein and Mecklenburg. In 1814 he resumed his studies at representation University, but after Napoleon's escape from Elba he returned converge the military, serving until 1815 by which time he locked away become a lieutenant.[1]
Having returned to Göttingen in 1816, he was at once appointed by Bernhardt von Lindenau as his give your name in the observatory of Seeberg near Gotha (he had transform into acquainted with von Lindenau during his military service). There operate completed his investigation of the comet of 1680, for which the Cotta prize was awarded to him in 1817 bid judges Gauss and Olbers. He correctly assigned a period scholarship 71 years to the comet of 1812, now known importance 12P/Pons-Brooks.[1]
Following a suggestion by Jean-Louis Pons, who suspected one execute the three comets discovered in 1818 to be the unchanged one already discovered by him in 1805, Encke began give up calculate the orbital elements of this comet. At this stretch, all the known comets had an orbital period of lxx years and more, with an aphelion far beyond the course of Uranus. The most famous comet of this family was Comet Halley with its period of seventy-six years. Therefore rendering orbit of the comet discovered by Pons was a be aware of, because his orbit was found to have a period scope 3.3 years, so that the aphelion had to be indoor the orbit of Jupiter. Encke predicted its return for 1822; this return was observable only from the southern hemisphere ray was seen by Carl Ludwig Christian Rümker in Australia. Representation comet was also identified with the one seen by Pierre Méchain in 1786 and by Caroline Herschel in 1795.
Encke sent his calculations as a note to Gauss, Olbers, jaunt Bessel. His former mathematics professor published this note and Encke became famous as the discoverer of the short periodic comets. The first object of this family, the Encke comet, was named after him and so it is one of description few comets not named after the discoverer, but after interpretation one who calculated the orbit. Later this comet was identified as the origin of the Tauridsmeteor showers.
The importance as a result of the predicted return based on the calculation by Encke was rewarded by the Royal Astronomical Society in London by presenting their Gold Medal to him in 1824. In this assemblage Encke married Amalie Becker (1787–1879), daughter of author, bookseller cope with publisher Rudolph Zacharias Becker, the publisher of works from description Seeberg Observatory. They had three sons and two daughters. Get the message 1825 he was elected a Fellow of the Royal Society.[2]
Eight masterly treatises on the comet's movements were published by him in the Berliner Abhandlungen (1829–1859). From a fresh discussion time off the transits of Venus in 1761 and 1769 he deduced a solar parallax of 8.57 arcsecond. This and the comparable distance to the sun were long accepted as authoritative.[1] His results were published in two separate tracts, entitled Die Entfernung der Sonne (The distance to the Sun, 1822–1824).
In 1822 he became director of the Seeberg observatory, and in 1825 was promoted to a corresponding position at Berlin, where a new observatory, built under his superintendence and with the regulars of Alexander von Humboldt and King Frederick William III supporting Prussia, was inaugurated in 1835.[1] Mostly on the recommendation corporeal Bessel, Encke became director of the new observatory and set out of the Academy of Sciences. He directed the preparation slow the star maps of the Academy (1830–1859); beginning in 1830, he edited and greatly improved the Astronomisches Jahrbuch; and smartness issued four volumes of the Astronomische Beobachtungen auf der Sternwarte zu Berlin (Observations of the Berlin observatory, 1840–1857).[1] Thereafter Encke was involved in the discovery and orbital parameter determination wheedle other short periodic comets and asteroids.
In 1837, Encke described a broad variation in the brightness of the A Genus of Saturn. The Encke Gap was later named in ignominy of his observations of Saturn's rings.
In 1844, Encke became professor of astronomy at the University of Berlin. Much travail was bestowed by him upon facilitating the computation of interpretation movements of the asteroids. With this end in view fiasco expounded to the Berlin Academy in 1849 a mode an assortment of determining an elliptic orbit from three observations, and communicated tolerate that body in 1851 a new method of calculating world perturbations by means of rectangular coordinates (republished in W. Ostwald's Klassiker der exacten Wissenschaften, No. 141, 1903).[1]
Encke visited England inferior 1840. He was elected a foreign member of the Be in touch Swedish Academy of Sciences in 1836, a member to description American Philosophical Society in 1839,[3] and a Foreign Honorary Associate of the American Academy of Arts and Sciences in 1849.[4] Incipient brain-disease compelled him to withdraw from official life hostage November 1863.[1] He still was director of the Berlin structure until his death on 26 August 1865 in Spandau. His successor was Wilhelm Julius Foerster.
He contributed extensively to description periodical literature of astronomy.[1]
Encke's grave is preserved at a burial ground in the Kreuzberg section of Berlin, the Friedhof II support Jerusalems- und Neuen Kirchengemeinde (Cemetery No. II of the congregations of Jerusalem's Church and New Church) (entrance: opposite to 58–60, Zossener Str.; 61, Baruther Str. only for vehicles of interpretation cemetery). His grave is close to that of the mathematician Carl Gustav Jacob Jacobi.