The Pacman Nebula is a bright emission nebula and part of an H II region in the northern constellation of Cassiopeia and
is part of the Milky Way's Perseus Spiral Arm. This 20×30 arcmin sized nebulosity is also associated with open cluster
IC 1590, several Bok globules and the multiple star, B 1. It collectively forms Sh2-184, spanning over a larger area of
40 arcmin. A recent distance from radio parallaxes of water masers at 22 GHz made during 2014 is estimated it lies
2.82±0.20 kpc (9200 ly) from us. 1