The Lobster Claw Nebula, Sh2-157, is an emission nebula in constellations of Cassiopeia and Cepheus at a distance of 8,000 light years.
The two arcs representing the pincers are thought to be the consequence of a Wolf Rayet star that belongs to the open cluster Markarian 50.
Also note, at the top right of the nebula, the presence of the open cluster NGC7510 located at 11400 Al from us.