In the image above, north is to the right and east is up.

Sharpless 155, also known as the Cave Nebula, Caldwell 9, or LBN 529, is a diffuse bright nebula within a larger nebula complex containing emission, reflection, and dark nebulosity, which is rich in color. It is located in the constellation Cepheus. The nebula gets its name "Cave Nebula" from the dark lane at the eastern side which ends at the brightest curve of emission nebulosity which gives the appearance of a deep cave when seen through a telescope visually. The bluish reflection nebula vdB 155 lies towards the lower left in this image, but barely registers in this Hα image.

Sharpless 155 - Cave Nebula, which this image is part of.