Williamina Fleming discovered IC 423 = HN 58 on 27 Jun 1888 during a photographic survey of the M42 region at the Harvard College Observatory. She noted a "irregular oval ring having diameters 3' by 5'. The position angle of the larger axis is about 165°." Edward Pickering published the discovery in the 1890 Harvard Annals publication (1890AnHar..18..113P) and is credited with the discovery in the IC. Fleming examined photographs taken with the Bache telescope, an 8-inch f/5.5 doublet covering 10 degrees square, with a magnifying glass.

400/500mm - 17.5" (12/26/00): fairly faint, large, slightly elongated NW-SE, ~5' diameter. A couple of mag 12.5 stars are superimposed. The edges fade into the background. Photographically, this reflection nebula has an irregular ring shape. Located 28' SE of mag 2.2 Delta Orionis (top star in Orion's Belt). Nearby IC 424 to the NE was not noted, though observed on 2/19/09.

Notes by Steve Gottlieb