This area lies just on the border between the constellations Cassiopeia and Cepheus. M52 (located in the upper left quadrant of this image) is a fine open cluster located in a rich Milky Way field. The distance of this cluster is not very well known, measurements indicate a range between 3.000 and 5.000 light years. It contains nearly 200 stars.

Situated about 35 arcminutes southwest of M52, just below the center of this image, lies the Bubble Nebula (NGC 7635) which surrounds the 7^th magnitude star HD 220057. Within the diffuse emission nebula lies a dark inclusion which appears as a faint and diffuse oval looking like a bubble, about 3.5 x 3 arcminutes in size, hence the name "Bubble Nebula". The bubble was probably formed when the nebulous material inside it was blown out by stellar wind of the bright OB star. The Bubble Nebula is difficult to see visually because of its low surface brightness.

Scattered around M52 and NGC 7635 are several other patches of nebulosity. Near the right edge NGC 7538 is located, another small and quite bright emission nebula. The large nebula near the lower right edge has the designation Sh2-157, an emission nebula looking somewhat like a claw. Most of the upper right quadrant of this image is occupied by the large and faint HII region Sh2-161.

M52 and NGC 7635 - Bubble Nebula Region, Wright-Newtonian photograph, which is part of this image.
M52 and NGC 7635 - Bubble Nebula Region in Hα, which is part of this image.
NGC 7635 - Bubble Nebula, Newtonian CCD image.