William Herschel discovered NGC 5364 = H II-534 = h1705 on 2 Feb 1786 (sweep 521) and recorded "pB, vL, gbM."

Bindon Stoney found it again on 14 Apr 1852 at Birr Castle and assumed it to be new, so John Herschel catalogued it also as GC 3703. Dreyer combined the two GC entries in the NGC. Harold Corwin suggests that JH's observation of h1678 (later NGC 5317), which he assumed to be new, may be a duplicate observation with a 5 minute error in RA.

200/250mm - 8" (5/21/82): faint, large, diffuse glow. Forms an unusual pair with smaller but brighter NGC 5363 14' N.

400/500mm - 17.5" (4/28/90): moderately bright, large, broad weak concentration, elongated SW-NE. Two mag 14 stars are 1.6' NW of center. Forms a pair with NGC 5360 8' WSW and NGC 5363 lies 14.5' N. Sixth of seven in the NGC 5363 group.

900/1200mm - 48" (3/1/19): at 488x; very bright, very large, oval 3:2 SW-NE, ~4.5'x3.0'. Strongly concentrated with a bright 1.5'x1.0' oval core that increased to a small bright nucleus with direct vision. There was a strong suggestion of spiral structure (arcs) in the large halo, but the contrast was too low to trace the arms. Two mag 14.2/14.4 stars are at the edge of the halo on the NW side and form the base of a thin isosceles triangle with the nucleus. Although the core region was well defined, it didn't appear as a ring.

Notes by Steve Gottlieb