Albert Marth discovered NGC 2238 = m 99 on 28 Feb 1864 with Lassell's 48" reflector on Malta. This is a small, nebulous area around a star in the western half of the Rosette Nebula but there was no mention of the entire nebula, which was first recognized by Lewis Swift and E.E. Barnard.

200/250mm - 8" (1/1/84): complete annulus easy visible in field at 42x or in 8x50 finder with filter as a large, soft ring surrounding the cluster.

300/350mm - 13.1" small knot on the west side of the Rosette Nebula. See NGC 2237 for description.

Naked-eye - (1/8/00): using an OIII filter, the apparent diameter of the cluster (NGC 2244) noticeably increases in size due to the surrounding nebulosity becoming visible. The overall brightness, though, is slightly decreased with the filter as the cluster is significantly dimmed.

Notes by Steve Gottlieb