NGC7380 – The Wizard Nebula

Can you see the Wizard? He is sitting upright, looking toward the right. He’s wearing a pointed hat and a cloak, and his hands are outstretched as he casts a powerful spell. He has a pointed nose and a bright blue eye. He looks angry!

On a less whimsical note, NGC7380 is actually an open star cluster that was discovered by Caroline Herschel (sister of Sir William Herschel) in 1787. The rich nebulosity surrounding the cluster was not appreciated until the advent of astrophotography, and in 1959 it was included in the Sharpless catalogue of H-II regions (emission nebulae featuring the strong Hydrogen-alpha spectral line) with the designation SH2-142.

The object is found in the constellation of Cepheus, near the border with Cassiopeia.  It is about 7200 light-years distant, and the part of the region shown in this image is about 55 light-years from top to bottom.

This is a narrowband image. As our eyes do not see  in narrowband, the images from the three filters which pass only photons from ionized sulphur (S-II), hydrogen (H-alpha) and oxygen (O-III) have been mapped to the conventional RGB channels our eyes are used to. The H-α signal dominates the image and some processing is necessary to allow the other wavelengths to be seen. Some tweaking to the hues has helped achieve a more æsthetically pleasing result.

In terms of the physics going on here, radiation from the hot young stars of the cluster is causing the edges of the dark clouds to glow as the stellar winds create bubbles of clear space around the stars.

North is toward the bottom right in this image: not only does this happen to show the wizard upright, but it was the actual orientation needed to acquire a suitable guide star.

Technical details:

Planewave CDK-14 corrected Dall-Kirkham reflector, FLI Proline P9000 cooled CCD camera and filter wheel with Astrodon 3nm narrowband filters. Total exposure times 10.5 hours through each filter (S-II, H-α and O-III). Processed in PixInsight and displayed using a modified SHO Hubble palette.