Rory Glasgow Caldwell Objects, Nebulae, Open Clusters

Caldwell 11 – The Bubble Nebula

There’s a lot going on in this image. The night before I took the shots that were used to compose it, I had imaged the same area using different exposure settings to see which would bring out the most detail. But I was not satisfied with the framing because there are just so many interesting things to see in this part of the sky. So, I reimaged the area and tried to capture as much as I could within the Dwarf 3’s field of view.

Caldwell 11 (Bubble Nebula), Messier 52 (Cassiopeia Salt-and-Pepper Cluster), NGC 7538 (Northern Lagoon Nebula), and NGC 7510 (Dormouse Cluster)
Caldwell 11 (Bubble Nebula), Messier 52 (Cassiopeia Salt-and-Pepper Cluster), NGC 7538 (Northern Lagoon Nebula), and NGC 7510 (Dormouse Cluster)

The group of stars in the upper left is open cluster Messier 52. To the lower right of that is The Bubble Nebula. The Northern Lagoon, which resembles a miniature version of the Lagoon Nebula, is toward the upper right. And the little Dormouse Cluster is in the lower right. Faint nebulosity is visible throughout most of the image.

The bubble in the Bubble Nebula is an area within a molecular cloud that has been cleared away by the stellar wind from a star named SAO 20575. Ultraviolet light from the star causes the hydrogen gas of the cloud to glow red.

SAO 20575
The arrow indicates the approximate location of the star that created the bubble. There are actually two stars in that area, but the scope doesn’t have sufficient magnification to separate them in this image.