Contains: M 43, NGC 1982, NGC 1977, M 42, Great Nebula in Orion, NGC 1976, NGC 1975, NGC 1973, The star 45Ori, The star θ2Ori, The star θ1Ori, The star 42Ori
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M42: Orion Nebula & Running Man (processing exercise)

Technical card

Resolution: 4500x2980

Dates: Feb. 19, 2017

ZWO Blue: 33x25" (gain: 129.00) -25C
ZWO Green: 34x25" (gain: 129.00) -25C
ZWO H-alpha 7nm: 30x60" (gain: 129.00) -25C
ZWO OIII: 30x60" (gain: 129.00) -25C
ZWO Red: 30x22" (gain: 129.00) -25C
ZWO SII 7nm: 30x60" (gain: 129.00) -25C

Integration: 2.1 hours

Avg. Moon age: 22.75 days

Avg. Moon phase: 43.62% job: 1570801

RA center: 83.793 degrees

DEC center: -5.222 degrees

Pixel scale: 0.919 arcsec/pixel

Orientation: 108.587 degrees

Field radius: 0.689 degrees


Revision A is the pure RGB image.

Not enough data for this - and this was at least the forth time I pointed my camera at Orion this year, so I'm not going to gather any more data, however, this was primarily just an exercise in processing for me - mainly using layers to bring out more detail as well as doing a nebula in RGB with a monochrome camera (this is my first!). Still need to find the right settings to avoid blowing out the core - maybe next year!



Chris Sullivan



Used S2 as a quasi-luminance channel.


Just narrowband in OSH.


Mix of RGB and narrowband.


Complete reprocess. I finally figured out how to use layer masks and used it for the core - it's washed out, but not completely. I constructed an artificial RGB using only SII (the only one that showed any core) and adjusted the color balance to match that part of the nebula. I also tried the luminance layering with the hydrogen alpha instead, and I think that came out well. No OIII used. The best part is: I finally got the Running Man nebula to be visible!


One last try. I incorporated some Ha into the red, some OIII into the blue and used SII as the luminance layer. I think there's a little more detail in the core, but the Running Man is back to being invisible.


A combination of the best parts of my last two revisions - I liked everything about revision E better than F except for the central part of M42. Getting better at masking...


I probably should have reprocessed from scratch, but I'm feeling a bit lazy. Anyway, all I did was stretch it and mask where that made things too bright. I'd still file this under "processing exercise".


A compromise between version G and H.

Sky plot

Sky plot


M42: Orion Nebula & Running Man (processing exercise), 


        Chris Sullivan

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