Date Posted: 2/27/2026
Date Taken: Four nights, from 10/20 - 11/16/2017
Scope: Planewave CDK 12.5 f/8, 2541mm
Camera: SBIG STL-11000 with Astrodon Tru-Balance E-Series Gen2 filters
Temp: -15C
Mount: Losmandy Titan
Guiding: On-axis via ONAG-XM and SX UltraStar at 2541mm; FocusLock real-time focus software.
Exposure: LRGB 185:110:105:95 All subs 5 min. Luminance unbinned, RGB binned 2x2.

Calibrated and Stacked with CCDStack2; RGB combine and DDP with MaximDL. Processed with CS4.

The Horsehead Nebula is perhaps the most iconic target for astrophotographers. All but invisible to the human eye, the striking red emission nebula is easily captured by digital camera sensors. The namesake Horsehead (catalogued as B33) is a dense cloud of dust in front of a bright emission nebula (catalogued as IC 434), creating the silhouette of a horse's head. The blue reflection nebula at upper left is catalogued as NGC 2023. It is part of the much larger Orion molecular cloud complex, which also includes the Great Orion Nebula and Barnard's Loop.

This is a partial re-process of an image originally taken in 2017. There was considerable glare from the bright star Alnitak, the eastern-most star in Orion's belt, just off the center-top of the frame. I did my best to tone it down without losing the faint nebulosity along the left side of the image.