M42 – The Orion Nebula

The Great Orion Nebula is visible to the naked eye in the night sky as the middle "star" in Orion's sword, which are the three stars located below his belt.

M42 is a stellar nursery, where new bright blue stars are in the process of forming. It is located at a distance of approximately 1,340 light years from Earth, and is the closest region of massive star formation to us. The M42 nebula is estimated to be 24 light years across. North is toward the left.

The blue reflection nebula north of M42 is NGC1977, also called the "Running Man Nebula."


Processing the Orion Nebula

A cluster of stars known as the Trapezium in the heart of the Orion Nebula are very bright compared to the surrounding nebulosity. If the image is processed to show the nebulosity, the core becomes so bright the individual stars can't be seen.

PixInsight offers tools to deal with such a "high dynamic range" (HDR) image. HDR tools blend short exposures that show only the stars and bright region with longer exposures that have the nebulosity plus the too-bright core. This blending preserves the nebulosity, but dims the core enough to make the stars visible.

To prepare, I acquired 50 120-second subframes of the nebulosity, plus 10 five-second subs of the stars. I processed these 50 subs normally, then combined them with Pixinsight's HDR tools to produce this final image.

Exposure  • Full image: 1⅔ hour @ -20°C (50 @ 120 seconds)
 • Core stars: 10 @ 5 seconds
 • Dusk flats
 • Camera position angle: 83.3°
Processing  • Calibration, registeraton, stretching and HDR processing with PixInsight
 • Final tweaking in Photoshop CS6
Date and Location  • December 24, 2019
 • Louisa County, Virginia, USA
Equipment
  • TMB-130SS APO refractor @ f/7 on an A-P 1200 mount
 • ZWO ASI-1600MC Pro color camera
 • Guided with an ST-402 camera on a 60mm f/5 scope
 • Imaging and autoguiding with MaxIm DL 6.20
 • Automated image acquisition with ACP Observatory Control

The Orion Region

This region of the winter sky contains several beautiful deep-space objects in addition to the Orion Nebula pictured above.

Hover your mouse over a yellow arrow below to see the name of an object. Click on the arrow to see my image of it.


Updated May 23, 2023