Cepheus Narrowband Mosaic (feat. Elephant Trunk, Flying Bat, and Squid)

In the Cepheus Constellation, both emission and reflection nebulas swarm. This is a four-panel mosaic of the former. The lower left shows the multicolored Elephant Trunk (IC 1396) and the upper right sports the red Flying Bat (Sh2-129) with the mysterious blue Squid (OU4) perched on top of it.

IC 1396 (lower left) refers to a star cluster “with nebulosity.” And while that cluster may be of great interest to scientists (especially because it’s one of the youngest in the galaxy at three million years old), it’s the nebulosity that interests dilletantes like me. The nebula is three degrees in diameter, which is six times the diameter of the full moon. Using hydrogen, sulfur, and oxygen filters reveals that it gushes with chemistry that portends of the star forming occurring within its folds. The Elephant Trunk (the dark patch extending from right to left toward the center) is 40 light-years long and is something slightly less than 2,800 light-years away.

In the upper right, Sh2-129—the Flying Bat Nebula—is visible in it’s perch 2,300 light years away. Mostly comprising ionized hydrogen, it poses a less imposing target than the Elephant Trunk—that is, until you consider the blue blob on top of it. That thing is the Squid Nebula (Ou4), which amateur Nicolas Outters first discovered in 2011. At first, it was thought to be a planetary nebula. But its size at 50 light years in length, and its bipolar complexity has called that determination into question.

Primary source: Annals of the Deep Sky, Vol. 5, Kanipe & Webb (2017)