Hartwig discovered 5 NGC objects while working at Strassbourg Observatory during his observations of comet d'Arrest 1883. The galaxy NGC 5405 in Bootes was found on March 3, 1883 with the 6.75" Repsold comet seeker. The position was subsequently measured with the 18" Merz refractor (erected in 1880); see AN 2507, Auffindung eines neuen Nebels, p. 173 (1883).The 3 other objects, the galaxies NGC 5176, 5177 and 5186 (forming a group) in Virgo, were found with the 18" on June 29, 1883; see AN 2688, Neue Nebel, p. 407 (1885). Swift and Hartwig are noted as discoverer for the galaxy NGC 6508 in Draco, but Hartwig was first on Sept. 19, 1883 using the 18" (see: Beobachtungen von neuen Nebeln, AN 106, 381 (1881)). Swift followed two years later with the 16" refractor at Warner Observatory.

Obituary: AN 219, 186 (1923)