James Dunlop discovered NGC 6253 = D 374 = h3657 on 14 May 1826 and described "a very faint nebula, of an irregular round figure, about 2' diameter, slightly bright towards the centre, easily resolvable into very minute stars, slightly compressed to the centre; this also precedes Epsilon Arae." His position was off by ~8' (too far southeast). JH recorded it on 8 Jul 1834 as "a small triangular cl 2' diameter; stars = 13m."

300/350mm - 14" (4/4/16 - Coonabarabran, 73x, 178x and 230x): fairly small 5' cluster, but quite rich with 60-70 stars mag 12-14.5 resolved at 230x. Stands out as a bright, partially resolved glow at 73x. Irregular shape but expands E-W on the south side and tapers on the north side. Contains no bright stars but a mag 8.9 star is just off the southwest side. Located 27' NNW of 4th magnitude Epsilon1 Arae. This well-studied cluster is an old, very metal-rich with an age of ~4 billion years.

Notes by Steve Gottlieb