Amazing Sky by Alan Dyer

This is a portrait of the complex of nebulosity in northern Cygnus, with many wreaths and arcs of hydrogen gas interspersed with patches and tendrils of dark dust of varying densities. The main nebula is the North America (NGC 7000) at upper left, with the smaller Pelican Nebula (IC 5067) beside it in the "Atlantic Ocean." At bottom right is the Gamma Cygni complex, aka the Butterfly Nebula or IC 1318, while at the bottom right edge is the small arc of the Crescent Nebula (NGC 6888). The field is filled with other fainter nebulas catalogued in the Sharpless and DWB catalogues. Above Gamma Cygni right of centre are two small patches of blue reflection nebulosity, van den Bergh 131 and 132. Numerous star clusters also populate the area, some yellowed by interstellar dust. The main region of dark sky at centre is the Northern Coal Sack.

This is a blend of exposures taken in "normal" broadband light and exposures taken in red H-alpha light, to bring out the faint nebulosity. This is a stack of 12 x 1.5-minutes through an URTH Night filter to cut sky glow and bring out nebulas somewhat, plus a stack of 14 x 1.5-minutes with a 12nm Astronomics Hydrogen-Alpha clip-in filter, all with the Canon RF135mm lens at f/2 (it is f/1.8 wide open) and the filter-modified Canon R camera, at ISO 800 for the broadband images and ISO 6400 for the H-a images. The camera was on the Sky-Watcher Star Adventurer 2i tracker with no autoguiding.

The H-a images were converted to monochrome B&W and blended in with a Lighten blend mode with just the R channel on, and with Blend If and Fill Opacity controls to affect the degree of blending and to prevent the nebulas from becoming too monochrome red, preserving the subtle range of red and magenta tones. PhotoKemi Nebula Filter and Star Reduction actions also brought out the nebulosity.

Taken from home on July 8/9, 2023 on a night with reduced transparency and with the waning quarter Moon rising as the H-a set began (I planned it that way!). Bu