NGC 2244, Open Cluster in the Rosette Nebula (NGC 2237)

NGC 2244 is an open cluster in the Rosette Nebula (NGC 2237), located in the constellation Monoceros. The hot young stars in the cluster create a strong solar wind pushing out on the Rosette Nebula, giving the Rosette Nebula its characteristic doughnut shape.

The Rosette Nebula, NGC 2237, is an emission nebula composed of hydrogen. Radiation from the hot young stars (O type) excites the hydrogen gas causing it to glow. (NASA Science)

This image is a narrowband image (HOOS). It enhances the emission nebulas contribution of H-alpha, OIII, and SII.

The table below shows the RGB channel assignments as well as the addition of a yellow channel. Assignments are as follows:

Channel --> Narrowband

Red --> H-alpha

Green --> OIII

Blue --> OIII

Yellow --> SII

Stars are standard RGB color.

The purpose of this Narrowband image is to show the composition of the emission nebula. The solar wind from the star cluster is blowing the gas outward. Hydrogen compared to oxygen and sulfur is very light. Therefore oxygen and sulfur compose the inner part of the nebula. Hydrogen is located beyond the core of the nebula.

Image processed by Andrew Macica, original data from Telescope Live.

Imaging Details:

Observatory: IC Astronomy Observatory, Oria, Almería, Spain

Telescope: Takahashi FSQ-106EDX4

Aperture: 106 mm, w/ 0.73x focal reducer, f/3.6

Focal Length: 382 mm

Camera: QHY 600M Pro CMOS

Filters: Ha, OIII, OIII, SII

Total Exposure: 10 hours 0 minutes

Image Processing:

PixInsight 1.8.9-3 Ripley (x64);

BlurXTerminator, NoiseXTerminator, StarXTerminator (RC Astro);

Adobe Photoshop 25.12.4;

Adobe Lightroom Classic 15.0.1

Instruction on PixInsight from Adam Block Studios.