William Herschel discovered NGC 5427 = H II-310 = h1735, along with NGC 5426, on 5 Mar 1785 (sweep 380). See description under NGC 5426.

On 18 Apr 1855, R.J. Mitchell (Lord Rosse's assistant) wrote, "The n one is spiral? 3 stars in it. To myself it appeared to have a single branch from below [np] the nucleus, running around the nf side. Mr. [Johnstone] Stoney [who was visiting between professorial duties] suspected two branches from n and f side, joined into one branch sf." Harold Knox-Shaw first identified this galaxy as an "open spiral" in 1915, based on a photograph taken with the 30" reflector at the Helwan Observatory.

300/350mm - 13.1" (6/4/83): fairly faint, moderately large, slightly elongated, very diffuse with an almost even surface brightness. Forms a pair with NGC 5426 2.3' S. Brightest in a group including NGC 5468 and 5472.

Notes by Steve Gottlieb