Above: A closer look (new rendition in December 2020)
The Higher resolution image is a re-work of the data, done in March 2020.
NGC 2359 (also known as Thor's Helmet) is an emission nebula in the constellation Canis Major. The nebula is approximately 3,670 parsecs (11.96 thousand light years) away and 30 light-years in size. The central star is the Wolf-Rayet star WR7, an extremely hot giant thought to be in a brief pre-supernova stage of evolution. It is similar in nature to the Bubble Nebula, but interactions with a nearby large molecular cloud are thought to have contributed to the more complex shape and curved bow-shock structure of Thor's Helmet.
The nebula has an overall bubble shape, but with complex filamentary structures. The nebula contains several hundred solar masses of ionised material, plus several thousand more of unionised gas. It is largely interstellar material swept up by winds from the central star, although some material does appear to be enriched with the products of fusion and is likely to come directly from the star. The expansion rate of different portions of the nebula varies from 10km/s to at least 30km/s, leading to age estimates of 78,500 - 236,000 years. The nebula has been studied at radio and x-ray wavelengths, but it is still unclear whether it was produced at the class O main sequence stage of development, as a red supergiant, luminous blue variable, or mainly as a Wolf-Rayet star.
Imaging telescopes or lenses: Takahashi FSQ130ED
Imaging cameras: QSI 6120
Mounts: Takahashi EM 400 Temma 2M
Guiding telescopes or lenses: Takahashi FS60CB
Guiding cameras: QHY CCD QHY 5 II
Focal Extender / Reducer: None
Software: PHD 2, Pleiades Astrophoto PixInsight , Astro Pixel Processor (for stacking), Sequence Generator Pro SGP (for capture)
Filters: Astrodon LRGB Ha (3nm) & OIII (3nm)
Accessories: Robofocus Focuser, ATIK EFW3
Original Resolution: 4250 x 2838
Dates: 28th Jan to 11th Feb. '18
Astrodon R 12 x 10'
Astrodon G 12 x 10'
Astrodon B 12 x 10'
Astrodon Ha 14 x 20'
Astrodon OIII 13 x 20'
Total Time: 15 Hours.
Center (RA, Dec):(109.623, -13.219)
Center (RA, hms):07h 18m 29.549s
Center (Dec, dms):-13° 13' 09.978"
Size:69.8 x 46.6 arcmin
Pixel scale:0.986 arcsec/pixel
Orientation:Up is 90.4 degrees E of N
Ha & OIII in the image: