Edward Austin discovered NGC 3315 = HN 40, along with NGC 3097 and 3317, on 24 Mar 1870 with the 15" Merz refractor at the Harvard College Observatory (Annals of Harvard Observatory, Vol 13, #207). There is nothing at his position. RNGC (as well as Laubert's 1981 ESO list) identifies ESO 501-047 as NGC 3315. While this identication is possible, Austin mentioned a "star 1' NW" which does not apply to this galaxy and no mention is made of the bright star which would have interfered with the observation.

However, 30' N of Austin's position is ESO 501-048 at 10 37 19.2 -27 11 30 (2000) which has a 10th magnitude star 1' NW. Based on Austin's visual description and a probable digit error in declination, this identification appears more likely and is the one used in ESO-Uppsala and RC3. Corwin originally listed this number as a duplicate of NGC 3314 (which Austin observed the same night) but now agrees the 30' error in declination is was more likely. This galaxy was listed by Knox-Shaw in a table of new nebulae (1912) found on plates taken at the Helwan Observatory between 1909-11. The RNGC candidate for NGC 3315 is 17' south of ESO 501-048.

400/500mm - 18" (3/17/07): faint, small, elongated 3:2 WNW-ESE, 0.3'x0.2'. Located 40" SE of a mag 11 star and 13' N of mag 4.9 HD 92036. HCG 48 lies 9' NE. This member of AGC 1060 (Hydra I) has a disputed identification due to a poor discovery position.

600/800mm - 24" (3/28/17): fairly faint, fairly small, slightly elongated, 25" diameter, high surface brightness, gradually increases to the center. A mag 11 star is off the west side [42" from center]. Similar to NGC 3305. Located 13' N of mag 4.9 HD 92036.

Notes by Steve Gottlieb