Celestial hemisphere:  Southern  ·  Constellation: Canis Major (CMa)  ·  Contains:  NGC 2359
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NGC 2359 Thor’s Helmet in Canis Major, Mark Wetzel
NGC 2359 Thor’s Helmet in Canis Major
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NGC 2359 Thor’s Helmet in Canis Major

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NGC 2359 Thor’s Helmet in Canis Major, Mark Wetzel
NGC 2359 Thor’s Helmet in Canis Major
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NGC 2359 Thor’s Helmet in Canis Major

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Description

Gold Canyon and Arizona City, Arizona
January 2-30, 2021

Reprocessed 2/5/2023

NGC 2359 is an emission nebula in the constellation Canis Major.  It was captured with narrowband filters, Hydrogen-alpha (Ha) and Oxygen-III (OIII).  Weather permitting, I took 10-minute exposures for each subframe and collected many hours of data over the month of January.  This false color image assigns Ha to Red and OIII to the Green and Blue channels (HOO).  Stars were taken with red, green and blue filters.

Reprocessing (2023):

Since I have had a good run reprocessing old DSO data sets using my current workflow and new PixInsight tools, I decided to reprocess Thor’s Helmut as an HOO false color image and add a RGB filter stars image.  After running the WBPP script, I created an RGB false color image combining Hydrogen-alpha and Oxygen III narrowband masters as HOO.  RGB broadband filter subframes were used to create a stars only image.  The  Spectrophotometric color calibration (SPCC) tool was used to calibrate the RGB stars image.  BlurXTerminator was used to deconvolve color and extracted luminance images.  After denoising with NoiseXTerminator, the GeneralizedHyperbolicStrecth tool was used to stretch HOO, luminance and stars images.  StarXTerminator was applied to remove the stars in the stretched state giving better results than in the linear state.  The stars were lightly saturated.  The nebula luminance image was sharpened with the MultiscaleLinearTransform tool, and the contrast was enhanced with the HistogramEqualization tool run with three circular kernel sizes (356 with 12 bit resolution, 128 with 10 bits, 64 with 8 bits).  The HOO starless color nebula image was blurred.  The sharpened luminance was combined with the HOO color image.  Finally, the stars were added using PixelMath with the opscreen() method in the combine function.

Description:

Thor’s Helmet is an interstellar bubble blown out as a fast wind from the central star as it pushes out through the surrounding molecular cloud at very high velocities.  The central Wolf-Rayet star is an extremely massive giant which is in a pre-supernova stage of development.  The ionized gas clouds are rich in hydrogen and especially oxygen which give the red and blue-green colors.  NGC 2359 is 15,000 light-years away and it is 30 light years across (SkySafari Pro).

Imaging details:

Celestron 9.25" Edge HD SCT
Celestron 0.7x focal reducer
Celestron off-axis guider with ZWO ASI174MM mini guide camera
Celestron CGEM II mount
ZWO ASI 1600MM Pro cooled monochrome camera (-10C)
36mm ZWO Hydrogen-alpha, Oxygen-III, Red, Green, Blue filters

Software:    Sequence Generator Pro, PHD2 guiding, Celestron CPWI mount control,
    PixInsight and Photoshop 2021/2023

Hydrogen-alpha    10 min x 99 subframes (990 min), Gain 139, Offset 21, 1x1 binning
Oxygen-III    10 min x 79 subframes (520 min), Gain 139, Offset 21, 1x1 binning
Red    4 min x 20 subframes (80 min), Gain 139, Offset 21, 1x1 binning
Green    2 min x 34 subframes (68 min), Gain 139, Offset 21, 1x1 binning
Blue    2 min x 35 subframes (70 min), Gain 139, Offset 21, 1x1 binning

Total integration time: 28.8 hours

Comments

Revisions

  • NGC 2359 Thor’s Helmet in Canis Major, Mark Wetzel
    Original
  • NGC 2359 Thor’s Helmet in Canis Major, Mark Wetzel
    B
  • Final
    NGC 2359 Thor’s Helmet in Canis Major, Mark Wetzel
    C

C

Description: Improvements to overall appearance and corrected over-shrunk stars.

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NGC 2359 Thor’s Helmet in Canis Major, Mark Wetzel