Sh2-308: The Spawn of a Wolf-Rayet Star (Alex Woronow)

Sh2-308: The Spawn of a Wolf-Rayet Star

Sh2-308: The Spawn of a Wolf-Rayet Star

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OTA: FSQ106 f/5
Camera: QHY 600 M
Observatory: Telescope Live (Aus-2)
Date of Capture: Dec '23
Date of Processing: Jan '24

Exposures:
H: 25 x 300 sec
O: 25 x   "
S: 24 x   "
Total Exposure time: 6.1 hours
Image Width: 3.7 degrees

Processing Tools:
1.   Commercial: PixInsight, Topaz, Photo Director 365
2.   Pixinsight Addons: NoiseXTerminator, BlurXTerminator, StarXTerminator, Normalize Scale Gradient
3.   My Scripts: NB_Assistant, AC_Restar, Subframe Weighting Tool (Excel w/ J. Hunt), ColorTweaker, StarTweaker

Target Description:
Although Wikipedia unequivocally states this "is an HII region … composed of ionized hydrogen," the narrowband filters and the color show a dominantly OIII composition. Perhaps the intensity of the star's winds and radiation have dispersed that hydrogen, and the lagging, heavier oxygen is what we now observe?

The central star (visible in this image) is a Wolf-Rayet star, a massive, very hot, young star that has shed the gasses that compose this nebula.

Processing Description:
Using an approximate mapping of the narrowband wavelengths into their equivalent RGB to subsequently be able to color calibrate the stars set the foundation for this image's colors. Of course, between this mathematical contortion and the replacement of the stars lays a battery of operations that affected the final color. These included linear fitting, photometric color calibration, (star removal), noise removal (yes, that can affect color), dehazing, image clarification, and probably others I have forgotten to include.

Starting from narrowband data, this final image cannot exactly depict the nebula colors, but neither does the Hubble Palette! I am pleased with the artistic coloration of the image; I hope you enjoy it, too.

Statistics:
Distance: 4.5K ly
Apparent Magnitude: 7
Average Surface Magnitude: 24
Apparent Span:35 arc-minutes
Pixel Span at Target: 30B km

Alex Woronow

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Status	Advanced success
Started	...
Astrometry.net job	9043489
PixInsight job	VHHUM93VFVWC9IZ9XDRPLUVJH75W43W8
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	06h54m10s.77
RA (top/left)	06h45m22s.40
RA (top/right)	07h01m31s.94
RA (bottom/right)	07h02m50s.82
RA (bottom/left)	06h46m58s.66

Dec (center)	-23°55′59″.9
Dec (top/left)	-24°50′23″.3
Dec (top/right)	-25°21′45″.2
Dec (bottom/right)	-22°59′50″.8
Dec (bottom/left)	-22°29′04″.8

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