Albert Marth discovered NGC 6623 = m 377, along with NGC 6619, on 6 Jun 1864 and noted "pF, S, R, bM." His RA is 6 seconds too large. Kobold measured an accurate micrometric position in 1892 (published in 1907).

400/500mm - 17.5" (7/16/88): faint, fairly small, slightly elongated NW-SE, bright core, diffuse halo. Located 4.1' NW of mag 8.6 SAO 85932. Pair with NGC 6619 11.4' WSW.

600/800mm - 24" (7/15/15): fairly faint to moderately bright, moderately large, roundish, ~0.9' diameter, sharply concentrated with a very small bright nucleus. A mag 14 star is 45" NE of center. Resides in a rich star field 4.1' NW of mag 8.8 HD 168670. NGC 6619 lies 11' SW.

MCG +04-43-027 = PGC 61744 is at the south edge of the halo [27" S of center]. At 375x it appeared as an extremely to very faint knot, round, 12" diameter.

Notes by Steve Gottlieb