John Herschel discovered NGC 2580 = h3123 on 5 Feb 1837 and described a "cluster 7th class; R; p rich; insulated; 10' diam; stars 12m, nearly uniform." His position is ~1.0' SE of center of this cluster.

300/350mm - 13.1" (3/24/84): 15-20 stars mag 10-13 within a rectangle of stars. A brighter double star is close north. Located 44' NE of NGC 2567 and 47' SE of NGC 2571 in a group of 4 open clusters along with NGC 2587 53' NNE.

Notes by Steve Gottlieb