Description (Wikipedia)
Alnitak (ζ Orionis) is a triple star system at the eastern end of Orion's belt and is 1,260 light-years from the Earth. Alnitak B is a 4th-magnitude B-type star which orbits Alnitak A every 1,500 years. The primary (Alnitak A) is itself a close binary, comprising Alnitak Aa (a blue supergiant of spectral type O9.7 Ibe and an apparent magnitude of 2.0) and Alnitak Ab (a blue dwarf of spectral type O9V and an apparent magnitude of about 4). Alnitak Aa is estimated as being up to 28 times as massive as the Sun, and to have a diameter 20 times greater. It is the brightest star of class O in the night sky.

The Flame Nebula, designated as NGC 2024 and Sh2-277, is an emission nebula in the constellation Orion. It is about 900 to 1,500 light-years away. The bright star Alnitak (ζ Ori), the easternmost star in the Belt of Orion, shines energetic ultraviolet light into the Flame and this knocks electrons away from the great clouds of hydrogen gas that reside there. Much of the glow results when the electrons and ionized hydrogen recombine. Additional dark gas and dust lies in front of the bright part of the nebula and this is what causes the dark network that appears in the center of the glowing gas. The Flame Nebula is part of the Orion Molecular Cloud Complex, a star-forming region that includes the famous Horsehead Nebula. At the center of the Flame Nebula is a cluster of newly formed stars, 86% of which have circumstellar disks. X-ray observations by the Chandra X-ray Observatory[5][6] show several hundred young stars, out of an estimated population of 800 stars. X-ray and infrared images indicate that the youngest stars are concentrated near the center of the cluster.

The Horsehead Nebula (also known as Barnard 33) is a small dark nebula in the constellation Orion.[2] The nebula is located just to the south of Alnitak, the easternmost star of Orion's Belt, and is part of the much larger Orion Molecular Cloud Complex. It appears within the southern region of the dense dust cloud known as Lynds 1630, along the edge of the much larger, active star-forming H II region called IC 434. The Horsehead Nebula is approximately 422 parsecs or 1,375 light-years from Earth. It is one of the most identifiable nebulae because of its resemblance to a horse's head.

Personal note
This is a 2 panel mosaic of Alnitak, the Flame nebula, and the horsehead. To get sufficient exposure time for a good quality picture, I restricted myself to Ha, at which this area has the strongest signal. I might add O3 and S2 at a later stage. Lots of stuff happening in this area, with many nice details to zoom into.

Panel 1: Alnitak area, 78x300s Ha (6.5 hr)
Panel 2: IC434 area: 68x300s Ha (5.7 hr)

Workflow
Pixinsight: WBPP, EZ denoise, Maskedstretch, GradientMergeMosaic, Histogram transformation, Curves, LocalHistogramEqalization


Please let me know your feedback and your suggestions on how to improve further. Thank you!