William Herschel discovered NGC 5430 = H II-827 = h1738 on 17 Mar 1790 (sweep 948) and logged "eF, S, E, but nearly R." CH's reduced position is 3' north of UGC 8937. JH measured an accurate position on a single observation.

200/250mm - 8" (4/24/82): faint, small, round. Located southeast of NGC 5376 and NGC 5389.

400/500mm - 17.5" (6/7/97): fairly faint, fairly small, elongated ~2:1 NNW-SSE, brighter core containing a stellar nucleus. A mag 14-15 "star" is involved at the south-southeast end. This "star" may confuse the apparent position angle of the galaxy as the major axis (including halo) is N-S. A faint pair of mag 14.5 stars follows by 2.0'.

The stellar object at the south-southeast end is a strong HII emission knot (Ho 569b = Mrk 799a) thought to contain a large number of type-O and Wolf-Rayet stars.

17.5" (4/5/97): moderately bright and large, elongated 5:2 NNW-SSE, 2.0'x0.8', brighter core increases to an occasional stellar nucleus. A mag 15 "star" is close southeast and a mag 14.5 pair at 12" separation lies 2.0' ENE of center.

600/800mm - 24" (7/1/16): at 375x; moderately to fairly bright, elongated 5:2 NNW-SSE, ~2'x0.8', contains a small bright elongated core (bar). The surface brightness in irregular with some interesting structure. I had an impression of a spiral arm extending north on the east side of the halo.

A fairly faint nonstellar knot (Holm 569B), 6"-8" diameter, is at the southeast end of the bar [21" from center]. There is a small dip in brightness between the central region and the knot. Bill Keel considered the knot an extremely luminous HII region, but a recent paper assumes NGC 5430 is a minor merger and the "knot" is an off-center dwarf satellite with a triggered star formation.

Notes by Steve Gottlieb