Heinrich d'Arrest discovered NGC 4257 on 21 Apr 1862 with the 11" refractor at Copenhagen Observator while observing nearby NGC 4261. His description mentions a mag 18 star 2' south, though the star is closer to mag 14-14.5. The discovery was listed in his sample preliminary results published in 1862 (AN 57, 337).

400/500mm - 17.5" (3/24/90): very faint, small, edge-on WSW-ENE, low even surface brightness. Located in a large group with NGC 4261 7' NNE.

600/800mm - 24" (4/28/14): fairly faint, fairly small, elongated nearly 3:1 WSW-ENE, 32"x12", pretty smooth surface brightness. Two mag 14/15 stars 1.2' S and 1.8' S are collinear with the galaxy. Located 7' SW of NGC 4261 and 10' SW of NGC 4264 in a field with numerous NGCs.

Notes by Steve Gottlieb