The Jellyfish Nebula, IC 443, is the remnant of a supernova, after a star exploded thousands of years ago. It's around 5,000 light years from Earth. It is not the source of UFOs above Canada.
The photo includes about 9.5 hours of imaging time and 5 hours of processing time. I used a different combination of tools this time — some PixInsight but more Photoshop than usual — and I'm quite happy with the result.
Preprocessing (PixInsight)- Weighted Batch Preprocessing
- Dynamic Crop
- (I skipped Dynamic Background Extraction for this one)
- BlurXTerminator
- NoiseXTerminator
Narrowband (PixInsight)- StarXTerminator
- ArcsinhStretch
- PixelMath to combine as follows:
- R: "SII"
- G: "((OIII*Ha)^~(OIII*Ha))*Ha + ~((OIII*Ha)^~(OIII*Ha))*OIII"
- B: "OIII"
- Export as 16-bit TIFF
RGB (PixInsight)- Channel Combination
- Image Solver
- Spectrophotometric Color Calibration
- ArcsinhStretch
- Generalized Hyperbolic Stretch
- Export at 16-bit TIFF
Composite (Photoshop)Photoshop processing isn't linear like PixInsight! But here are a few highlights (excuse the pun) from my processing.
- Added the stretched Ha with a "Luminosity" blending mode
- Masked out the bright star to reduce the narrowband contribution, and use the RGB version only
- Added the RGB stars from PixInsight with a blending mode of "Screen"
- Doubled-up on the brightest star (screen on screen?) to brighten that without modifying other parts of the image
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