8 star shines in the middle of it. NGC7789 is an open cluster that improves with aperture. Shining at mag. Opinions vary as to whether 300 or 1000 stars reside here. Easy to find, this cluster sits mid-way between Sigma and Rho Cassiopeiae.
Total brightness is mag.
Stars range from mags. Messier thought he saw nebulosity, but there is none. The nebulosity, sometimes called the Pacman Nebula, responds to filters, and even better to photography. It lies in a rich field. This is a mag 10.6 grouping with members at mags 12.5 and fainter.