Born Guben, (Bradenburg, Germany), 18 December 1639
Died Berlin, (Germany), 25 July 1710
Gottfried Kirch, probably the most prominent German astronomer around 1700, is best known for having published long series of calendars and ephemerides. Also an active observer, Kirch was famous for his discovery of the bright comet of 1680. In 1686 Kirch detected the variable star χ Cygni, the third known variable star after Mira itself (detected 1639) and Algol (1669). His career culminated in his appointment as the first permanently engaged astronomo ordinario at Berlin on 18 May 1700.
Kirch was born during the 30 Years’ War. His father, Michael Kirch, a tailor, had to flee with his family from Guben, and the childhood of Gottfried was therefore rather restless. He probably never received a university degree. However, Kirch had good contacts with Erhard Weigel , who taught mathematics, astronomy, geography, and physics at the University of Jena from 1653 to 1699. Weigel recommended Kirch to the prominent astronomer Johann Hevel , who had a well-equipped private observatory at Danzig. In 1674, Kirch worked there for some months.
Before 1700 Kirch’s living conditions were rather unstable and his income not safe. While he probably earned most of his money as a calendar maker, he also worked as a teacher. Kirch lived in Guben, in Langgrün, Thuringia, until 1676, in Leipzig Saxony 1676–1680, in Coburg 1680–1681, again in Leipzig 1681–1692 and in Guben 1692–1700, and finally in Berlin 1700–1710.
At Langgrün, Kirch married Maria Lang in 1667; they had seven sons and one daughter. Maria Kirch died in 1690. In 1692 he married his second wife, Maria Margaretha Winkelmann, and they had five daughters and two sons. His second wife supported him strongly in calculating calendars and in carrying out astronomical and meteorological observations. Maria Kirch became widely known as the “Kirchin,” i.e., the “feminine version” of the name Kirch. Also, many of their children supported and followed them in their astronomical tasks, especially Christfried Kirch and Christine Kirch .
From 1663 until his death, Gottfried Kirch carried out astronomical observations quite regularly, usually using small instruments. His observations concerned nearly all types of celestial objects or phenomena, from sunspots to comets to variable stars. In 1678, he published a paper on Mira, based partially on his own observations of this variable star. Kirch became most famous as the discoverer of the extremely bright comet of 1680, now designated C/1680 V1. This was the first telescopic comet discovery in history. In 1681, Kirch described the galactic open star cluster that is now designated as Messier 11. In 1686, he found χ Cygni to be a variable star and determined its period as 404.5 days.
The main astronomical activity of Kirch was, however, the computation and editing of calendars for the general public and the publishing of astronomical ephemerides. His first calendars appeared in 1667 in Jena and Helmstedt, later in Nuremberg and Königsberg, e.g., the “Christen-, Jüden- und Türcken-Kalender oder alt und neu Jahr-Buch,” and the “Alter und neuer Schreib-Kalender in Cantzeleyen, Aemptern, Raths-und Richter-Stuben … nützlich zu gebrauchen.” Kirch’s ephemerides (e.g., Ephemeridum Motuum Coelestium), first published in 1681, are mainly based on Johannes Kepler ’s Rudolphine Tables, but Kirch added some corrections.
In 1700, Kirch accepted the call to the permanent position as the astronomo ordinario at Berlin. This position was created by Friedrich III, Elector of Brandenburg, in his edict of 10 May 1700, the so called Kalenderpatent. This edict followed the decision of the German Protestant states in 1699 to introduce from 1700 onward a new “improved” calendar, which was essentially identical to the Catholic Gregorian Calendar (except for the computation of the date of Easter) and which should be calculated by qualified astronomers. The edict introduced a monopoly for this calendar in the Electorate of Brandenburg (later in Prussia) and imposed a “calendar tax.” The corresponding income was used for paying the astronomer and other members of the Berlin Academy of Sciences, which was founded on 11 July 1700. Friedrich III promised also to erect an observatory at Berlin, but this observatory was not actually inaugurated until 19 January 1711.
Kirch started his expected calendar work immediately and in 1700 was able to prepare the first calendar of this series, the “Chur-Brandenburgischer Verbesserter Calender Auff das Jahr Christi 1701.” In his calendar work Kirch was strongly supported by his wife Maria Margaretha Kirch and by an assistant astronomer, Johann Heinrich Hoffmann (1669–1716), who followed Kirch as astronomo ordinario after Kirch’s death in 1710. The Berlin calendars were quite popular and certainly gained much from Kirch’s long experience in calculating and editing calendars. His calendar experience was also the strongest motivation for calling him to the position of the astronomer at Berlin, in spite of his advanced age of 60 years.
The observing conditions at Berlin were not the best. Kirch had to use small transportable instruments, located either in his own house or (after 1708) in the tower of the unfinished Berlin Observatory. After 1705, he was sometimes allowed to use the better-equipped private observatory of Baron Bernhard Friedrich von Krosigk (1656–1714). Nevertheless, Kirch also collected and published many astronomical observations at Berlin. For example, he discovered in 1702 the globular cluster that is now designated as Messier 5, and his wife and he were among the independent discoverers of comet C/1702 H1.
After his death, his calendar work was continued (somewhat unofficially) by Maria Margaretha, officially by Hoffmann from 1710 to 1716, and then by his son, Christfried, from 1716 onward, and then again unofficially by his daughter Christine. We should remark here that the prominent Berlin astronomer Johann Bode had strong personal links to the Kirch family: Bode’s first two wives were grandnieces of Christine, and hence great granddaughters of Kirch. Thus, Kirch established what is probably the longest family tradition in calendar and ephemerides making.
Two astronomical objects are named for Kirch: A lunar crater Kirch and the minor planet (6841) Gottfriedkirch.