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

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 and the next four images are a sequence. The difference between the images are the channels used to create the images. The channels in the sequences are as follows: HaLRGB, HaRGB, HOOS (NB), LRGB and RGB. Generally speaking, the progression from this image to the last, the intensity of the H-alpha channel decreases and fine structure in the background becomes more visible. The description for each image provides further details.

This particular image enhances the emission nebulas contribution to H-alpha.

This image is the HaLRGB. Essentially two images are combined to produce this image. The first is a hydrogen alpha image, the second is a color LRGB image. The emission nebula is primarily composed of excited hydrogen glowing red in the hydrogen alpha wavelength of 656.28 nm. Excited hydrogen also has a small contribution in the hydrogen beta wavelength of 486.1 nm (blue). The contribution of both the hydrogen alpha and the hydrogen beta produces a slightly magenta color. With this image the H-alpha channel only contains the contribution to just 656.28 nm. The contribution from the hydrogen beta wavelength, 486.1 nm (blue), comes from the LRGB image. Thus the color of the emission nebula has a slight magenta color.

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, LRGB

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.