The emission nebula Sharpless 171, the open cluster Berkeley 59 and the associated dark nebula LDN 1267, 1268, 1269, 1270, 1271 and 1275 are captured in this image taken with a hydrogen alpha filter. Astronomers believe that the Sharpless 171 nebula is about 3,000 light years distant. The Berkeley 59 cluster is believed to be about 2 million years old. There are probably a total of 9 stars in the cluster which are responsible for ionising the Sharpless 171 nebula.
It is easy to imagine while viewing this image that the Berkeley 59 cluster sits in a vast hollowed out sphere. The ionizing radiation from the cluster has been hollowing out the sphere and the ionizing radiation of the Berkeley 59 stars is also causing the gas on the inner surface of the sphere to emit photons at the various wavelengths which we see here as the red glow of Sharpless 171. The strong ionising radiation is also eroding the gas and dust pillars visible on what appears to be the inner surface of the sphere. It is also easy to imagine that the dark nebula within the field and adjacent to the Berkeley 59 cluster – LDN 1269 – 1271 and LDN 1275 – are on the surface of the sphere nearest to us and thus what we are seeing as dark nebula is the back side of dust and gas clouds that are part of the Sharpless 171 complex but which lie between us and the Berkeley 59 cluster. Several stars which appear to be part of the Berkeley 59 cluster appear dimmed by the intervening dust and gas.
Total integration time for this image was 5 hours. The imaging scope was the Takahashi FSQ-106EDX IV with the ZWO ASI1600MM-C.
The photons for this image were captured on September 1 – 2, 2017 at the San Diego Astronomy Association site at Tierra del Sol, San Diego County, California.
Click on the image below for a slightly larger version. Follow this link to my Astrobin page for a full resolution view.