William Herschel discovered NGC 6058 = H III-637 = h1946 on 18 Mar 1787 (sweep 718) and recorded "vF, eS, 300 showed 2 very close stars affected with nebulosity, a very small star in the field with it was perfectly free from that nebulosity." John Herschel made two observations on consecutive sweeps and noted "pB, vS, R, almost stellar or psbM; diam 10"."

George Johnstone Stoney, Lord Rosse's assistant on 5 May 1850, wrote "strongly suspect to be an annular neb with a star near the center. On 5 Apr 1851, his brother Bindon wrote, "like [NGC 2392], dark ring plainer seen on preceding part of neb; vS * north, about 3/4' diam of neb off. The following part of dark ring a little broader than the preceding part." Samuel Hunter made a sketch on 9 May 1861 and this was included at the last minute in the 1861 publication.

The spectrum was recognized as a PN by Campbell and Moore. Based on a Crossley photograph at Lick, Curtis (1918) reported "an irregular oval fading out at ends of major axis, brightest at north and south edges; 25"x20" in pa 77°."

200/250mm - 8" (7/5/83): at 100x, faint, very small, round, even surface brightness. At 200x, an extremely faint mag 13.5-14 central star is visible surrounded by a small faint halo. Two mag 9 stars to the north form an rough isosceles triangle.

300/350mm - 13.1" (7/5/83): fairly faint, small. Fairly easy central star at 166x, two stars to the north form an equilateral triangle. Can take 333x.

400/500mm - 17.5" (5/27/00): fairly bright, fairly small, slightly elongated NNW-SSE, 25"x20". Contains an easy mag 13.5 central star, which stands out well at all powers. At 380x, the halo appears to brighten surrounding the central star. Nicely framed within a triangle of mag 9-10 stars.

17.5" (5/30/92): fairly bright, small, 20" diameter. A bright mag 13 central star is easily visible. Located within a bright isosceles triangle consisting of mag 8.8 SAO 45874 4.8' NW, mag 8.7 SAO 45881 6.3' NE and a mag 10 star 3.5' S.

600/800mm - 24" (7/14/18): at 375x; bright mag 13 central star encased in a well defined 0.4' halo. At 500x the halo is clearly elongated N-S, ~25"x20", slightly fainter at north and south end. A very faint mag 15.9 star is close off the north edge.

Notes by Steve Gottlieb