Cat's Paw, emission nebula in Scorpius.
This is a Ha RGB image consisting of 162 x 8min subframes: 84 Ha and 26 for each of RGB filters. ZWO ASI1600MM C camera at Gain 100 and cooled to -16C (May 16&17) and -26C (May 28). Image scale 2.2 arcsed/pixel. Field of view in final picture 1d 53' 45" x 1d 36' 37"
Processing: 20 flat frames for each filter calibrated with exposure equal dark frames, plus 20x480s dark frames. Ha RGB subframes calibrated, registered and integrated with WeightedBatchPreProcessing in Pixinsight. Conventional processing with MureDenoise, DynamicBackgroundExtraction and Deconvolution. RGB master processed with BackgroundNeutralization and PhotometricColourCalibration.
Ha integrated into RGB image following the tutorial by Kayron Mercieca at Light Vortex
https://www.lightvortexastronomy.com/tutorial-combining-lrgb-with-narrowband.htmlAs no images were acquired using a Luminance filter, I extraced the L channel from the RGB image and blended in the Ha following the PixelMath approach by Kayron. The modified RGB and L imaged were stretched with HistogramTransformation then combined using LRGB combination. The non-linear composite image was sharpened using MultiscaleLinearTransformation, denoised with TGVDenoise, had the dynamic range adjusted with HDRMultiscaleTransformation, and had star intensities reduced with MorphologicalTransform.
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