Andrew Cooper
Sep 12, 2024    Waikoloa, HI (map)
20cm f/6 Newtonian, Cave Astrola @ 45x
Seeing: 7 Transparency: 6 Moon: 0%

Big, bright, very rich, easily visible in the finder, a swarm of stars 7th magnitude and fainter, fully resolved, listed as 40' in diameter, but that is but part of a very rich region that extends well beyond that particularly to the south, the small rich cluster NGC 2156 is a patch of haze on the southwest margin, another small cluster NGC 2157 lies 35' further west from NGC 2158, the entire region is simply splendid, a low power sweep revealing an area rich with clusters, bright stars, and filled with rich galactic starfield

Andrew Cooper
Apr 18, 2022    Waikoloa, HI (map)
15cm f/4 Newtonian, Makaʻiki mk2 @ 27x
Seeing: 7 Transparency: 6.5 Moon: 0%

Large, bright and obvious, very rich and fully resolved, stars 8th magnitude and fainter, obvious in the 30mm finder, extents not well resolved fading gradually into a rich galactic starfield, an excellent RFT target

Andrew Cooper
Sep 14, 2015    Hale Pohaku, HI (map)
15cm f/5 Newtonian, Makaʻiki @ 19x
Seeing: 8 Transparency: 6 Moon: 0%

A bright cluster off the toe of Gemini, rich, 20' in diameter, fully resolved, a couple bright stars surrounded by a swarm of dimmer members in a heavy Milky Way starfield

Andrew Cooper
Mar 1, 2011    Hale Pohaku, HI (map)
46cm f/4.5 Newtonian, Deep Violet @ 60x
Seeing: 7 Transparency: 6 Moon: 0%

Large, about 30', bright, rich, an odd void at the center, arranged in clumps with a notable chain of stars at the northeast leading out from the center, NGC2158 visible 30' to the southeast

Andrew Cooper
Oct 21, 2006    TIMPA, Avra Valley, AZ (map)
12x36 Canon Image Stabilized Binoculars

Bright, well resolved, good sized, easily found off the 'toe' of Gemini

Andrew Cooper
Dec 3, 2004    Sentinel, AZ (map)
46cm f/4.5 Deep Violet

Large, bright, very rich, a heavy concentration of hundreds of stars in a rich star field, stars arranged in clumps and chains, an oddly vacant area at the center, NGC2158 visible as a faint patch 23' to the southwest

Rev. T.W. Webb
May 19, 1885    Hardwick, Herefordshire, England (map)
24cm Reflector

Beautiful and extensive region of small stars, a nebula to the naked eye. How differently La.'s 24-in. mirror shows it, his own words will best tell:-- 'A marvellously striking object. No one can see it for the first time without an exclamation... The field of view 19' in diam. and angular subtense 53-1/2°, is perfectly full of brilliant stars, unusually equal in magnitude, and distribution over the whole area. Nothing but a sight of the object itself can convey an adequate idea of its exquisite beauty.' Sm. observes that the stars form curves, often commencing with a larger one. There is an elegant festoon near centre, staring with a reddish star; 9-in. spec., '71. No ruddy star, Feb 18, 21, '82. Es., pale yellow, '93. Between ε Gem. and ζ Tau, a little n; in fine region. About 1/2° sp, just beyond a group of outliers, is NGC2158 (H. VI 17), a faint dim cloud of very minute stars.

― Celestial Objects for Common Telescopes, T. W. Webb, 1917

Captain William Henry Smyth
Oct 19, 1836    No. 6 The Crescent, Bedford, England (map)
150mm f/17.6 refractor by Tully 1827

A cluster, near Castor's right foot, in the Galaxy, discovered and registered by Messier in 1764. It presents a gorgeous field of stars from the 9th to the 16th magnitudes, but with the centre of the mass less rich than the rest. From the small stars being inclined to form curves of three or four, and often with a large one at the root of the curve, it somewhat reminds one of the bursting of a sky-rocket.

Under favourable circumstances this cluster can be distinguished by naked eye; it therefore may be comparatively near us. It must be sought on the line between Castor and ζ on the tip of the Bull's southern horn, at exactly one-quarter of the distance from the latter: or a line led from α Leporis through Betelgeuze, and extended 18° beyond, will strike upon it.

This object being so handy to the point assumed by Hipparchus, as the north extreme of the ecliptic, I swept for anything which might be on the actual spot, under the necessary corrections, in RA 6h , and Dec. N 23° 27'. After some search, I found a star of the 12th magnitude, but too small for having its place differentiated for any permanent purpose.

― A Cycle of Celestial Objects Vol II, The Bedford Catalogue, William Henry Smyth, 1844

John Herschel
Feb 19, 1827    

A large, coarse, pretty rich cluster of stars of 9th to 16th magnitude, which fills 2 or 3 fields, but chiefly one in which are about 100 stars.

Charles Messier
Aug 30, 1764    

Cluster of very small stars, near the left foot of Castor, at a little distance from the stars Mu & Eta of that constellation. M. Messier has reported its position on the chart of the comet of 1770, Mem. Acad. 1771, pl. VII. Reported in the English Atlas.

― Connaissance des Temps, 1781