NGC 7635 "The Bubble Nebula"

NGC 7662, The Bubble Nebula
This color image (click here for a larger version) is made from wide band blue and green filtered exposures, and a narrow-band H-alpha filter used for both the red channel and the luminance channel. The total exposure was 90 minutes. The H-alpha filter isolates light produced by glowing ionized hydrogen. The image was taken with Kopernikís 20 inch telescope working at F/5.3 using an SBIG STL-1301E CCD Camera.

Quote from Burnham's Celestial Handbook:

The faint nebulosity NGC 7635, (is) located about 36' distant (from M-52) toward the SW........ The most curious feature of this nebulosity is a faint ovoid arc of gas about 3' in size, resembling a great ghostly bubble (200'' Hale telescope photograph on page 522 of Burnhamís). This object is often classed as a planetary nebula, but can hardly be considered a typical member of that odd family of objects; it may be an ancient nova remnant. Some 2' to the SW lies another large field of faint nebulosity, unnumbered on standard star atlases, but measuring more than one degree in diameter. This field lies on the Cassiopeia-Cepheus border........