1686 Kirch went to Leipzig, where he observed the comet of this year together with the farmer and astronomer Christoph Arnold (1650-1695). There he married Maria Margarethe Winckelmann (Feb 25, 1670 in Panitsch - Dec 29, 1720 in Berlin), who had learned astronomy from Arnold; she was his second wife.
In 1688, he invented and charted the now obsolete constellation Sceptrum Brandenburgicum, the Brandenburg Scepter, consisting of only four stars of mag 4..5, below the first bend of Eridanus and west of Lepus.
In 1700, Kirch was appointed as the first astronomer of the Prussian Royal Society of Sciences by King Frederick III.
He devoted much time to the study of the double star Mizar (Zeta Ursae Majoris).
Kirch discovered M11 in 1681 and M5 on May 5, 1702. Also discovered the variability of the Mira variable Chi Cygni in 1687.
At age 71, Gottfried Kirch died on July 25, 1710 at Berlin.
He was honored by naming a Moon Crater after him (39.2N, 5.6W, 11.0 km diameter). Asteroid (6841) Gottfriedkirch, provisionally designated 2034 P-L, has been discovered on September 24, 1960 by C. J. van Houten, I. van Houten-Groeneveld and T. Gehrels from Palomar Observatory; it also bears the provisional desgnations 1954 YQ and 1994 PX33 from independent sightings.