Koehler was born in Gauernick (near Dresden), Germany on December 15, 1745. He was secretary of the Astronomical Society of Leipzig from 1771 to 1776. His observatory in Dresden was equipped with two Dollond achromatic refractors of 6 ft and 10 ft focal length and an 8 ft Gregorian reflector. Koehler found 9 objects, 6 are new. Among them are the central Virgo galaxies M 84, 86 and 87 (recently revealed by the author). Since 1772 Koehler has compiled a list of 20 nebulae, published in 1779: Koehler G., Beobachtung des Kometen vom Jahr 1779 und Entdeckung einiger neuer Nebelsterne, Astronomisches Jahrbuch oder Ephemeriden für das Jahr 1782, 151-157 (1779). Koehler is also credited with the discovery of the cluster M 67 in Cancer (according to Bode this was before 1779). Köhler died at Dresden on Sept. 19, 1801.
| D | N | NI | Y | M | D | I | T | Discoverer | Observer | Name | Con | Type | S |
| 1 | N | 2682 | 1779 | Rr | v | Messier 6.4.1780 | M 67 | CNC | II2m | 4 | |||
| N | 3031 | 1779 | Rr | v | Bode 31.12.1774 | Mechain Aug. 1780 | M 81, Bode's Nebulae | UMA | Sb | 1 | |||
| N | 3034 | 1779 | Rr | v | Bode 31.12.1774 | Mechain Aug. 1780 | M 82, Bode's Nebulae | UMA | Sd | 1 | |||
| 1 | N | 4374 | 1779 | 5 | 5 | Rr | v | Messier 18.3.1781 | M 84, Markarian Chain | VIR | E1 | 1 | |
| 1 | N | 4406 | 1779 | 5 | 5 | Rr | v | Messier 18.3.1781 | M 86, Markarian Chain | VIR | E3 | 1 | |
| 1 | N | 4486 | 1779 | 5 | 5 | Rr | v | Messier 18.3.1781 | M 87 | VIR | E2/P | 1 | |
| 1 | N | 4621 | 1779 | 4 | 11 | Rr | v | Messier 15.4.1779 | M 59 | VIR | E5 | 1 | |
| 1 | N | 4649 | 1779 | 4 | 11 | Rr | v | Oriani 12.4.1779 Messier 15.4.1779 |
M 60 | VIR | E2 | 1 | |
| N | 6838 | 1779 | Rr | v | de Chéseaux 1745 | Mechain 28.6.1780 | M 71 | SGE | GCL | 5 |
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An early Gregorian reflector from the Count Löser (1742), who made the 8 ft for Koehler.