William Herschel discovered NGC 4438 = H I-28.2 = h1275, along with NGC 4435, on 17 Apr 1784 (sweep 199) and recorded "two B, cL nebula." His single position matches the pair NGC 4435 and 4438. See NGC 4435 for more on the confusion with the identifications. JH made 3 observations and recorded (sweep 242) "pB; L; lE; 60".", along with an accurate position.

300/350mm - 13.1" (5/14/83): bright, bright core, larger but more diffuse than NGC 4435.

400/500mm - 17.5" (4/25/87): bright, elongated 5:2 SSW-NNE, small bright core. Forms a striking pair with NGC 4435 4.5' NNW. The core is not as large or bright as NGC 4435. Located in the center of the Virgo cluster 23' E of M86.

600/800mm - 24" (4/28/14 and 5/29/14): very bright, very large, very elongated 5:2 or 3:1 SSW-NNE, 3.0'x1.0'. Contains a large, bright elongated core that increases to a very small, very bright nucleus. With averted vision, much fainter irregular extensions (with an uneven surface brightness) significantly increase the outer diameter. The southwest "plume" is not aligned with the major axis of the galaxy and spreads further towards the west.

Notes by Steve Gottlieb