Took the plunge and got myself a cooled camera so here is first light on the Lobster Claw nebula. It's a bit of a learning curve getting used to the camera but I'm getting there! I was really fortunate to have a few clear nights after getting it to try it out - when does that ever happen with new astro gear?! Predictably the Welsh weather has returned with rain and clouds so it's time to get to processing those images...
Processed using Pixinsight as follows:
Pre-processing: Calibration and debayered to separate R,G, and B channels. Aligned and integrated with local normalisation.
Background: Dynamic Crop and DBE to take out the borders and even out the background
Linear Noise Reduction: TGV denoise followed by MMT - method from Jon Rista (
https://jonrista.com/the-astrophotographers-guide/pixinsights/effective-noise-reduction-part-1/ ).
Luminance Image:
- RGB channel combination, Extraction of luminance (colour image discarded), Deconvolution - method from Jon Rista (
https://jonrista.com/the-astrophotographers-guide/pixinsights/proper-use-of-regularized-richardson-lucy-deconvolution/ )
- Very slight stretch till the nebulosity is just visible and then StarXterminator (
https://www.rc-astro.com/resources/StarXTerminator/) to get starless luminance image and stars image (that helped to keep the stars from bloating)
- Further stretch of starless lum image using Generalised Hyperbolic Stretch (
https://ghsastro.co.uk/ ) and curves
- Local Histogram Equalisation
- MMT sharpening
- ACDNR for noise reduction
- PixelMath to add the star image back
Chrominance Image:
- PixelMath to create synthetic Ha image (0.9 * R + 0.1* B) and synthetic OIII image (0.6 * G + 0.4 * B) - no deconvolution used
- Stretched as for luminance image
- PixelMath to create colour image - dynamic combination as per
https://thecoldestnights.com/2020/06/pixinsight-dynamic-narrowband-combinations-with-pixelmath/- Curves Transformation to tweak saturation, hue etc.
- ACDNR for noise reduction
- PixelMath to add stars back
- Convolution to blur image
LRGB image:
- LRGB combination
- Export as TIFF
- Photoshop for final crop, minor tweaks and export to JPEG
Comments