Nébuleuse de la Chauve-Souris volante

Stewart Sharpless catalogued it in 1959 as number 129; it covers 140 arcminutes on a side, and its arc shape earns it the nickname of the Flying Bat. In the photo, the red arc, thicker on its left, fills the frame and spills beyond it, around a group of bluish stars. The main photo, whose caption reads “HO”, takes up the dual-band exposure of the second one and extends it; neither of them shows Ou4, a very faint nebula that the APOD reveals in the same place, in the blue-green of oxygen.

Sources: Wikipédia en français, Sh2-129, NASA, APOD du 27 octobre 2016, « A Giant Squid in the Flying Bat ». A figure wrong? Report it.