THE THOR'S HELMET NEBULA
- NGC 2359
- Deepsky 2860mm LRGBHOO
- Constellation Canis Major

NGC 2359, also known as the Duck Nebula or Thor's Helmet, is a Wolf-Rayet ring nebula (a special type of emission nebula) in the constellation Canis Major, in English "Big Dog" south of the celestial equator. NGC 2359 has an apparent magnitude of +11.45 and an angular extent of 9′ × 6′. It is about 15,000 light-years distant from the solar system and has a diameter of about 20 light-years. The fog is expanding at 26 kilometers per second. The mass of the bubble is estimated at 70 to 140 solar masses.
In contrast to most of the others, this emission nebula is not excited to glow by O stars (like the Orion nebula) or white dwarfs (like the planetary nebulae), but by a Wolf-Rayet star: HD 56925 (WR 7 , HIP 35378). This 11.4 mag star is located just west of the center of the bubble and has an effective temperature of about 50,000° Celsius. The star builds up enormous radiation pressure that blows the outer layers into interstellar space. The matter ejected and propelled outward over time forms a bubble that marks the shock front of the ejection.
Spectral analysis suggests that the bubble-shaped nebula is likely composed of a mixture of material lost from the central Wolf-Rayet star in a previous ejection and the surrounding interstellar medium, which is being swirled, condensed and condensed by interaction with its strong stellar wind is ionized.

Equipment & recording dates:
Astronomical Telescope for Educational Outreach (ATEO-3) is a 12.5" f/9 (2860mm focal length) Quasar Optics Ritchey Chretien owned and operated by Franck Jobard. Image processing and post-processing Thomas ArtOfPix Großschmidt.
Lights: L 29x 600s // R 13x 600s, G 15x 600s & B 20x 600s // hA 36x 600s & OIII 42x 600s (flats, darks, bias calibrated, dithering)
Location: Chile, Rio Hurtado Valley, owned and operated by Franck Jobard. Remote Telescope Insight Observatory.

Image editing:
mainly Pixinsight, plus Photoshop, Lightroom, GraXpert, BTX Blur Terminator, Noise Terminator, Star X Terminator