Friedrich Argelander

Friedrich Wilhelm August Argelander (March 22, 1799 - February 17, 1875), was a German astronomer, author of the Bonner Durchmusterung, a detailed stellar atlas which collected the position and brightness of 324,198 stars in the northern hemisphere.

Semblance

Argelander was born in 1799 in the town of Memel (Klaipeda). At that time the town belonged to Prussia and the largest city in the area was Königsberg (Kaliningrad), where in 1817 Argelander began his education in science.

By 1810 Friedrich Wilhelm Bessel (1784-1846) had become the director of the local observatory and professor of astronomy at the University of Königsberg. Argelander was very enthusiastic about astronomy thanks to Bessel, first becoming his student and 1820 assistant at the Königsberg observatory.

He obtained his doctorate in 1822 with a critical review of the observations of John Flamsteed (1646-1719), who had published an uncorrected summary of his observations from 1676 to 1705 in 1712.

Bessel got Argelander a job in 1823 as an observer at the observatory at the University of Turku (Swedish: Åbo), Finland, then called the Turku Academy. Argelander became the director of the observatory and in 1828 professor of astronomy at the university. In 1828 the university moved to Helsinki due to a fire that had destroyed most of the university buildings in Turku (Åbo) in 1827. In Turku he had worked on the movement of the stars, where he wrote the results in 1837 in the book On the Proper Motion of the Solar System.

From 1836 to 1837 he began with the first plans for an observatory in Bonn, which was to be financed by King Frederick William IV of Prussia (1795-1861).

During the construction period in 1843, Argelander published a catalog of fixed stars visible to the naked eye, where he created a unique method for estimating the brightness of stars relative to one another. The catalog was called Uranometria nova, perhaps in memory of the star atlas Uranometria by Johannes Bayer (1572-1625) written in 1603. This calculation method was also used for a collection of 22 known variable stars published in 1850.

For the determination of the proper motion of the Solar System related to the universe that surrounds it, Argelander concluded that he did not have enough data for the correct answer about which center the Sun and the stars were moving towards, if there were any. some. In this way he dedicated himself to studying the positions of the stars in the northern hemisphere from 1852 onwards in Bonn.

In 11 years he measured the position and brightness of 324,198 stars between +90° and -2° declination with his assistant Eduard Schönfeld (1828-1891) and Adalbert Krüger (1832-1896) and collected these observations in an index numbered by decline.

This catalog first published in 1863 became known as the Bonner Durchmusterung (Bonn Measurement, abbreviated BD). In the same year Argelander founded the Astronomical Society together with Wilhelm Foerster (1832-1921), among others. The objective of this society was to make a complete map of the sky. The society independently published a catalog of stars between 80° and -23° declination in 1887, containing about 200,000 stars, known as the Astronomische Gesellschaft Katalog (AGK).

Argelander died in Bonn at the age of 76 in 1875.

Other works

• Observations astronomicae in specula universitatis Fennicae factae. 3 vols. Helsinki (Helsingfors) 1830-32
• DLX stellarum fixarum positiones mediae ineunte anno 1830. Helsinki 1835
• Über die eigene Bewegung des SonnensystemsSt. Petersburg 1837)
• Durchmusterung des nördlichen Himmels zwischen 45° und 80° nördlicher Deklination. Bonn 1848
• Neue Uranometrie. Berlin 1843
• Durchmusterung der Himmelszone zwischen 15° und 31° südlicher Deklination. In: Astronomische Beobachtungen auf der Sternwarte zu Bonn 1846-1852
• Atlas des nördlichen gestirnten Himmels. Bonn 1857-1863: 40 letters

Acknowledgments

• The moon crater Argelander bears this name in his memory.
• The asteroid (1551) Argelander also commemorates its name.