Nicolas-Louis de Lacaille discovered NGC 2546 = Lac II-4 = D 563 = h3116 in 1751-1752 using a 1/2-inch refractor at 8x during his expedition to the Cape of Good Hope. He recorded II-4 as follows: "One sees with the naked eye two neighboring confused groups of stars; but with the telescope they are faint, distinct stars, very numerous & very close together."

James Dunlop observed the cluster on 8 May 1826 and recorded "a large cluster of stars of mixt magnitude, rather extended figure, not rich in very small stars." He made two observations and his position is 17' N of center (typical error). JH made 3 observations from the CGH, first recording on 1 Feb 1835 "a cluster 8th class of about 20 bright stars in an oblong, 8' long, 3' broad."

200/250mm - 8" (3/28/81): ~25 stars, rich, elongated. At the edge of a large, scattered field of stars.

300/350mm - 13.1" (1/30/06 - Costa Rica): this very large, bright scattered cluster was just visible to the naked eye close south of a brighter, hazy naked-eye patch of unresolved stars. The field is beautifully rich, at least 45' diameter though there was no distinct border. The star field looks impressive beyond the edges of the 66' field of the 20 Nagler. On the northwest side is a rich, elongated strip of ~20 stars that is quite eye-catching. Includes a few pairs and a neat triple with a fairly close unequal mag pair at the SSW end of the elongated strip.

13.1" (2/18/04 - Costa Rica): this cluster is a very bright, scattered field of stars that completely fills the nearly 40' field at 105x. Partially resolved in the 9x50 finder. At the NW edge is a rich elongated strip of two dozen stars including a couple of close, unequal pairs and tight fainter triple. John Herschel's description applies to this denser group of stars. A mag 6.4 star (h4051 = HD 68450) with two mag 13.5 companions is off the NW side of the larger group but does not appear to be part of the cluster and a similar star lies to the SE (HD 68862).

13.1" (1/18/85): ~75 stars, bright, very large, scattered, overfills 30' field.

Notes by Steve Gottlieb