November 17, 2024

M42/43 – Reflection/Emission Nebula in Orion

M42/43 – Reflection/Emission Nebula in Orion

Telescope: Astro-Tech 8” f/8 Ritchey-Chretien, Orion Atlas EQ-G

Camera: ZWO ASI071MC Pro, 0C, Gain 200, Baader Mk III MPCC

Filter: Orion Imaging Skyglow Filter

Guide scope: Astro-Tech 60mm, Meade DSI Pro II, PHD

Exposure: 95x90s, saved as FITS

Darks: 32x90s, saved as FITS

Flats: 32×0.2s, sky flats taken at dusk

Average Light Pollution: Red zone, Bortle 8, fair transparency

Lensed Sky Quality Meter: 18.5 mag/arc-sec^2

Stacking: Mean with a 2-sigma clip.

White Balance: Nebulosity Automatic

Software: Nebulosity, Deep Sky Stacker, Photoshop

This is one of several first-light images taken with my shiny new ASI071MC Pro. The 071 uses an APS-c size chip which makes good use of the relatively flat field of the RC8. It’s neat to compare this camera with the D5300a that I have been using for much of the past year.

M42 is the large section of this nebula while M43 is the smaller, comma shaped section above M42. The red regions of the nebula is light from interstellar hydrogen set aglow by newly formed stars, the smoky blue/gray is starlight reflecting off of interstellar dust, and the dark lanes are veils of dust in the foreground. In this particular image I love the fine detail in the smoky gray rift between M42 and M43.

Visually, M42 appears as a delicate puff of gray smoke about midway along the length of a string of stars that form the Sword of Orion. This line of stars point southwards from the three bright stars that form the distinctive Belt of Orion that is rising in the east as twilight deepens this time of year. The Sword and M42 are easily visible in binoculars or a small telescope. Under dark skies The Great Nebula can even be seen without any optical aid. In a modest telescope the nebula shows some wonderful fine structure in its triangular core that often gets lost in processed images like this one. The core hosts a tiny group of 4 young, relatively bright stars called the Trapezium.