NGC 2359, Wolf-Rayet star WR7

Constellation: Canis Major

NGC 2359, also known as Thor’s Helmet, is an emission nebula located 11’960 Ly away in the constellation of Canis Major. The nebula is excited by the ionising radiation of the central star WR7 (HD 56925), which is a Wolf-Rayet star. It is a WN star, i.e. it shows many many lines of ionized nitrogen. It is estimated that WR7 is about 13 times heavier, 1.26 time larger and 229’000 time more luminous than the Sun. It currently the 2nd smallest known WR star after WR2. Link to interactive sky chart.

Dates:

This is derived from the outstanding data taken by Martin Pugh during February and March 2025 (Martin’s website: Remote Astrophotography with Martin Pugh (martinpughastrophotography.space).

His telescope is located in Chile (Observatory: El Sauce).

Colour palette is RGBHOO.

Telescope & Mount:

Planewave CDK24 with 0.66x reducer (F4.37) on a Planewave L600 mount.

Imaging:

Camera: Moravian G3-61000 (bin 2×2)

Data:
Astrodon Lum: 21x300s
Astrodon Red: 24x300s
Astrodon Green: 25x300s
Astrodon Blue: 29x300s
Astrodon Ha: 38x300s
Astrodon O3: 37x300s

Total integration time: 14h 30′