I’ve got approx 6 hours of Ha and RGB data on the Horsehead and Flame Nebula. I need more, I aim for around 20 hours. In the meantime, I am enjoying practising processing using books and internet forums. Processing is hard, no doubt about it, and it is starting to click for me albeit slowly. I think the key is similar to normal photography. The best images are made in the camera no amount of processing will make a poor photo amazing. Anyway, here is the latest HaRGB combination of this target.
Processing Technique in a Nutshell
Linear Processing
Ha Linear:
- Dynamic Crop
- DBE
- Mask and AT Noise Reduction
- Invert Mask and Deconvolution using Star Mask and Local Deringing Support. Generate PSF using Dynamic PSF.
RGB Linear:
- Register against Ha Linear
- DBE
- Mask and AT Noise Reduction
- Invert Mask and Deconvolution using Star Mask and Local Deringing Support. Generate PSF using Dynamic PSF.
Create HaRGB Linear Image
Create a HaR image:
- Extract channels of Linear RGB.
- Use Pixel Math to create continuum map x 2. (http://pixinsight.com/tutorials/narrowband/theory/en.html)
- C1 = B/N
- Denoise using AT the C Map
- Use Pixel Math so Bnew = N * C1
- Repeat but this time C2 = Bnew/N
- Denoise C2
- Use pixel math so Bfinal = C2*N
- End result is HaR.
Create HaRGB:
- Use linear fit setting original R as reference and appy to the new HaR.
- Use channel combination to combine HaR with G and B from original image.
- Result is HaRGB.
Non Linear Processing
Stretch the Image:
- Use script Masked Stretch to initiall stretch the image.
- Use Histogram to final stretch the image. Adjust channels if needed so peaks are aligned on R, G and B.
Create LSS+SSS Using Masks:
- Create Star Masks to generate LSS and SSS
- Use Histogram Transformation to stretch LSS and SSS being careful not to clip any pixels.
- Combine LSS and SSS using PixelMath LSS+SSS
Further Processing:
- Use HDRMultiscaleTransform
- Use LocalHistogramEqualization using clone mask and also invert
- User CurvesTransformation for Saturation Boost and Contrast Boost with Star Mask
- Use ACDNR
Finishing Touches in PS:
- High Pass
- Merge Ha with RGB again with Luminosity set to 50%
- Add frame and text then save for web