First Light: Cygnus Loop

The Cygnus Loop is one of the iconic emission nebulae in the constellation Cygnus. This region of sky is very rich in stunning emission nebulae of different origin. One of these gas clouds is the Cygnus Loop – a large structure whose different parts go under a number of names: Eastern and Western Veil Nebula, Cirrus Nebula, Filamentary Nebula, Pickering’s Triangle, Network Nebula, Witch’s Broom, and more. The whole loop has an apparent diameter of about 3 degrees, this corresponds to 6 times the full moon.

All of this is the result of a single supernova explosion that happened, according to new findings based on data from the GAIA satellite, more than 20,000 years ago in a distance of about 2500 light years. The ejected outer shells of the original star now form the intricate filaments of gas that emit light in characteristic wavelength of atomic transitions.

This is a false-color narrowband images, which uses only two wavelength corresponding to the dominant Ha and OIII transitions. The blue regions indicate the presence of ionized oxygen, while the red regions are dominated by hydrogen gas.

Such a large target requires a large filed of view, an ideal case for our piggy-back system using a Samyang 135mm telephoto lens in combination with a cooled monochrome camera, the ATIK One 6.0. Using over 100 exposure of 300 sec each, with narrowband filter tuned to the Ha and OIII transition lines.