NGC 2359 (also known as Thor's Helmet) is an emission nebula in the constellation Canis Major. The nebula is approximately 15,000 light-years away and 30 light years in size. Known as a Wolf-Rayet star, the central star is an extremely hot giant thought to be in a brief, pre-supernova stage of evolution. It is similar in nature to the Bubble Nebula, 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.

[Source Wikipedia].

The image was captured with the iOptron CEM120 mount , the venerable Meade 12"LX200 SCT, and my Atik 383L+ mono CCD at F7.16 (2182mm FL).

Image subs were taken through Astronomik's narrowband filters of Ha, SII and OIII.

IMAGE information -- 2021

Ha: 51 subs (8.50 hr) on Feb 19th and 21st and Mar 3rd, 4th and 6th.

OIII: 51 subs (8.50 hr) on Feb 19th, 20th and 21st and Mar 3rd, 4th, 6th and 7th.

SII: 61 subs (10.17 hr) on Feb 20th and 21st and Mar 2nd, 3rd, 4th, 6th and 7th.

All exposures were at 10 minutes (600s) each, 1x1 bin and -10C.

Each of Ha, SII and OIII subs were individually integrated. The three assemblies then combined to create the color palette, using PixelMath and Juan Canejero's preference:

Red = 0.5SII + 0.5Ha

Grn = 0.15Ha + 0.85OIII

Blu = OIII

Luminance was created using only subs from the Ha filter.

Processing was done with PixInsight, following (for the most part) kayronjm's tutorial of Feb. 24th from several years back. Credit also goes to Rick Stevenson’s Color Mask Script and Christopher Gomez’s tutorial.

This is a slight crop, and North is up.

COMMENTS (this is becoming repetitive):

I had previously done this target in December of 2013. Unfortunately, this was the dark period when my (less than reliable) Dell Desktop decided to trash out a large part of my data. It not only lost images on its hard drive, but also took out a Western Digital external hard drive that had most of my images on it. Not real happy with Dell.

Anyway, I have only the JPEG image of this object from that time with which to compare. This one’s better.

Yes, it's better, but somewhat disappointing. There is a lot of integration time devoted to this subject and I was hoping for better results.