www.galaxies.se - by Ivar Hamberg

OBJECT: IC5146, SH2-125, Cocoon Nebula, LBN424

This is the Cocoon Nebula in Cygnus, SH2-125. An open cluster is "on top of" the nebula and designated IC5146. The embedded dark features are labelled Barnard168. The nebula is about 12 arc minutes across, and it is classified as a "reflection/emission" nebula. The red color comes from emission originated by ionization from the central star BD+46 (GSC3608:1446). There is also a blue patch of reflection nebula to the west of the main nebula, vdB147. In the background there are several patches of dark nebulae, LDN-objects. 

I made exposures over 3 nights in R, G, B, and Ha in a not-so-dark summer sky in August. Here I present the nebula in standard RGB colors. I tested also an S-II and O-III filter. The S-II gave some good contrast, but O-III did not show very much, indicating that it is not a "normal" emission nebula. All image files are dark and flat field corrected.

To the upper right there are 3 small LEDA galaxies, with distances of 500-1100 MLY. 

Orientation: South is up.