History

French astronomer Nicholas-Louis de Lacaille (also: de la Caille) discovered the cluster in 1751-1752 using a ½" telescope at 8x during his expedition to the Cape of Good Hope. He classified it as a star accompanied by nebulosity and noted: «Three small stars in a straight line, surrounded by nebulosity.» ^[8]

Scottish astronomer James Dunlop made five observations (first on 8 May 1826) using his self built 9-inch reflector, observing from his home at Parramatta (NSW) in Australia. He listed the cluster as Δ 304 with the description: «(λ Circini, Bode) Lacaille describes this as three small stars in a line with nebula. No particular nebula exists in this place. A group of about twenty stars of mixt magnitudes, forming an irregular figure, about 5' or 6' long, answer to the place of the λ. This is in the milky way; and there is no nebula in the group of stars except what is common in the neighbourhood.» ^[50]

John Herschel observing from South Africa listed this cluster as h 3616 with four observations in the Cape Catalogue: on 22 April 1835 (sweep 575) he logged «VII.; loose; scattered; brilliant; stars large; much more than fills field; 46 stars counted above 12th mag; chief star 7th mag taken.» ^[11]