Our present hope is to study [the nebulae] statistically, but until motions,either radial or transverse, have been detected we must content ourselves wit ht he problem of their distribution. The first step is ot make a systematic survey with powerful telescopes. Fath made a beginning by photographing each of the Kapteyn fields within reach of the Mount Wilson 60-inch reflector with uniform exposures fo one hour. He discovered more than eight hundred new nebulae, and confirmed the fact that the small nebulae avoided the Milky Way. This last is vital in its bearing on the question of whether or not those objects belong in our system.

Edwin P. Hubble — Photographic Investigations of Faint Nebulae, 1929