Processing story / Lion Nebula Sh2-132
Finding the Lion in gold, cyan and blue
More than 28 hours of narrowband exposure, a luminous cyan center, and gold and coral filaments. Separate nebula and star processing shaped this SHO portrait.
Photography and processing by Michael Page
- Integrated SHO exposure
- 28 h 36 min 40 s
- Light frames
- 206
- Per exposure
- 500 s
- From capture to stars
- 8 stages
Keep the luminous center and strengthen the boundaries
The aim was to give the warm filaments enough presence while preserving the bright center and the blue structure above it. Processing the nebula separately made local palette decisions possible; restoring the stars at the preferred strength completed the PixInsight stage. After the PixInsight recombination, final processing in Adobe Photoshop adjusted contrast and saturation and rotated the image for the published gallery presentation.
The last PixInsight contrast curve was left out because it flattened the bright center. The accepted image keeps the earlier tonal structure and restores the stars with a 90% Screen blend. Final contrast, saturation and image rotation were then completed in Photoshop for the gallery image.
See the difference
Two decisions, made visible
From the initial palette to the retained color
Compare the normalized stretched nebula with the accepted starless finish.
Drag the arrows on the image to compare. You can also use the arrow keys when the handle is selected.
Saved checkpoints with the same crop and display conversion. Several color, tone and local-contrast changes separate these images; this is not an isolated single-setting test.
The return of the stars
Compare the accepted starless version and final 90% Screen blend.
Drag the arrows on the image to compare. You can also use the arrow keys when the handle is selected.
Same framing, with no extra stretch or brightness matching for these exports.
At the telescope
- Telescope
- William Optics UltraCat 108
- Camera
- ZWO ASI2600MM Pro
- Hα filter
- Antlia Hα 4.5 nm
- O III filter
- Antlia O III 3 nm
- S II filter
- Antlia S II 3 nm
- Capture
- 500 s exposures · bin 1 × 1
- Camera settings
- Gain 100 · Offset 50 · −5°C
- Processing
- PixInsight SHO nebula and stars · Adobe Photoshop final contrast, saturation and rotation
| Channel | Frames | Exposure |
|---|---|---|
| Hα | 72 | 10 h 00 min |
| O III | 71 | 9 h 51 min 40 s |
| S II | 63 | 8 h 45 min |
216 exposures were acquired, totaling 30 h. The final integrations contain 206 exposures totaling 28 h 36 min 40 s. S II maps to red, Hα to green, and O III to blue. Stellar colors are mapped narrowband colors.
Keep exploring
See more of the night sky through the images and stories on StellarPix.