18th century French astronomer, Charles Messier, famously compiled a list of astronomical apparitions that were neither stars, planets, nor comets and which he called nebulae. These became known as Messier Objects and include star clusters, galaxies and “proper” nebulae.

Astronomy Picture of the Day featured one such on 29/8/19. The picture is copyright to A Bob Franke so i have not reproduced it here.

Is it just me or does that planetary nebula look like a biological cell as seen through a microscope?