Sh 2-155 (also designated Caldwell 9, Sharpless 155 or S155, or LBN529) is a diffuse nebula in the constellation Cepheus, within a larger nebula complex containing emission, reflection, and dark nebulosity. It is widely known as the Cave Nebula, though that name was applied earlier to Ced 201, a different nebula in Cepheus. Sh 2-155 is an ionized H II region with ongoing star formation activity,at an estimated distance of 725 parsecs (2400 light-years) from Earth.

Sh 2-155 was first noted as a galactic emission nebula in 1959 in the extended second edition of the Sharpless catalogue, being a part of the much larger Cep OB3 Association. Although Sh 2-155 is relatively faint for amateur observation, some of its structure may be seen visually through a moderately sized telescope under dark skies.

I've taken a total of 15 hours of exposures to make this image through a TEC140 with 0.7 focal reducer and ASI6200MM camera and Chroma SHO and RGB filters.  Except for 30 minutes each for R,G and B, most of the exposure is in narrowband.    The palette I used is OHS versus the normal SHO.     I just like it better in this image.