4231 4229
Cen
☀9.4mag
Ø 5.0'

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Note the group of stars described here is 12' S of ESO 171-SC14, the cluster identified as NGC 4230 in most sources including SIMBAD and ESO. ESO 171-SC14 is a cluster of roughly two dozen mag 13-14 stars in a 3' region just southeast of mag 8.4 HD 106826. A couple of mag 11 stars are 2' E and 3.5' NE of the mag 8.4 star, but these are detached.

John Herschel discovered NGC 4230 = h3386 on 5 Apr 1837 and described a "Cluster class VI. F; pL; irreg; 6'; resolved into stars 13, 14, 15m. Place of a * 12m, chief and near the middle of cluster." At his position is an unimpressive 5' group of star that is likely an asterism, with the brightest star 12th magnitude. This is the "cluster" identified by Harold Corwin as NGC 4230. Corwin notes that ESO (and SIMBAD) misidentify ESO 171-SC14 as NGC 4230. This group of stars is scattered southeast of a mag 8 star -- too bright not to have been mentioned by JH. See Harold Corwin's identification notes for more on this number.

300/350mm - 14" (4/4/16 - Coonabarabran, 73x and 178x): roughly 40 stars are resolved in a 7'x5' region (the outline is pretty arbitrary), roughly elongated SW-NE. Appears as an unimpressive asterism with no rich subgroups. A mag 11.5/13 pair at 13" separation is southwest of center with several mag 13-14.5 stars to its northeast. A mag 12 star 2' SW and a mag 11 star 4' SW of the central pair are all collinear. Located 18' SW of mag 5 Delta Crucis.

Notes by Steve Gottlieb