NGC 6823 and Sh2-86 - wonderfuluniverse.de

NGC 6823 and Sh2-86 from my backyard and remote

In 2015, I imaged the beautiful combination of the emission nebula Sh2-86, also known as NGC 6820, and the embedded open cluster NGC 6823 from my backyard in Krefeld using my CCD equipment. The image was acquired in HRGB, combining Hα data with broadband RGB to enhance the intricate emission structures while preserving the natural colors of the surrounding star field.

Eight years later, in 2023, I received a deep SHO narrowband dataset of the same region from Telescope Live, acquired under the pristine skies of Chile. The two images beautifully demonstrate the complementary strengths of HRGB and SHO imaging: the HRGB image presents the nebula with natural stellar colors, while the SHO data reveal the complex ionization structure of the gas in extraordinary detail.

Located in the constellation Vulpecula, Sh2-86 (NGC 6820) and NGC 6823 lie at a distance of approximately 6,000 light-years. At its heart lies the young open cluster NGC 6823, whose massive O- and B-type stars provide the intense ultraviolet radiation that ionizes the surrounding hydrogen cloud. The cluster is only a few million years old and represents one of the youngest stellar associations in this part of the Milky Way.

The nebula forms part of a much larger giant molecular cloud complex where star formation is still actively taking place. Deep narrowband images reveal bright ionization fronts, intricate filaments, and numerous dark Bok globules embedded within the glowing hydrogen gas. These compact clouds of cold molecular material are potential birthplaces of future stars, illustrating the ongoing cycle of stellar formation within the region.

One of the most remarkable features associated with Sh2-86 is the nearby Pillar of Vulpecula, a towering column of dense gas and dust extending several light-years into the surrounding nebula. Similar in appearance to the famous Pillars of Creation in the Eagle Nebula, this structure is gradually being eroded by the intense radiation and stellar winds from the massive stars of NGC 6823. Along its surface, compressed pockets of gas may eventually collapse to form a new generation of stars.

The SHO palette is particularly effective for this object because it separates the emission from different chemical elements, revealing the physical conditions within the nebula. Hydrogen dominates much of the cloud, while sulfur traces denser ionization fronts and oxygen highlights regions exposed to the most energetic radiation. The result is a richly detailed view of the interactions between massive stars and their surrounding interstellar environment.

The 2023 dataset from Telescope Live captures both the spectacular beauty and the scientific complexity of this active star-forming region. Combining the brilliant young stars of NGC 6823 with the glowing hydrogen clouds of Sh2-86, the image illustrates the intimate relationship between newly formed star clusters and the nebulae from which they emerge. It is an excellent example of how professional remote observatories enable amateur astrophotographers to explore some of the most fascinating stellar nurseries in our Galaxy.

The final HRGB image beautifully combines the natural colors of the stars with the enhanced hydrogen emission, revealing the complex interplay between the young open cluster and its surrounding nebula. It captures one of the finest star-forming regions in Vulpecula and demonstrates that, with careful acquisition and processing, detailed narrowband images of emission nebulae can be obtained even from a suburban backyard.

For the Telescope Live data the calibration, registration and the final processing was done with PixInsight. The result was as follows: