The Orion Nebula (Messier 42) is a diffuse emission nebula located in the constellation Orion. It lies below Orion’s Belt and appears as the central object in the Sword of Orion. M42 is one of the brightest nebulae visible in the night sky and represents a major region of active star formation. Situated approximately 1,300 light-years from Earth, the nebula spans roughly 25 light-years in diameter.

This image was made with a Nikon Z7II and a Nikon 600mm f/6.3 lens. Orion presents a challenge to image since the typical long exposures required to obtain nebula detail result in completely blowing out areas like the very bright central trapezium region.  A total of four different exposure sets, each shot at ISO 3600, were therefore made to properly capture the the varying brightness levels across the nebula. The final image is an HDR composite of stacks of 13 1-second, 48 3-second, 50 6-second, and 105 30-second exposures. This resulted in a total exposure time of just over one hour.

Star tracking was done with a Fornax LighTack II. The raw images were converted to TIF using RawTherapee, which were then aligned using Deep Sky Stacker. Each of the individual star aligned exposure sets were then stacked using sigma clipped averaging using program astro-sca.  The individual sigma-clipped averaged files where then HDR combined using Photoshop. The final HDR stack was then stretched using astro-color-stretch. 

The final stretch used a two pass root-power stretch (100, 2), a minor vignette correction of 20%, star size reduction, and final color correction. Some additional post processing adjustments were made with Capture One with a small amount of  final noise reduction using Topaz Denoise.

Both astro-sca and astro-color-stretch are Python programs and are available free here in the astrophotography software downloads page.