Orion Nebula - M42

This is one of the most dramatic objects in the sky.

M42 is south of Orion's Belt in the constellation of Orion. It is one of the brightest nebulae, and is visible to the naked eye in the night sky. It is seen as the middle "star" in the "sword" of Orion, which are the three stars located south of Orion's Belt.

Distance to Earth: 1,344 light years

Radius: 12 light years

Wiki: The Orion Nebula is one of the most scrutinized and photographed objects in the night sky, and is among the most intensely studied celestial features.[8] The nebula has revealed much about the process of how stars and planetary systems are formed from collapsing clouds of gas and dust. Astronomers have directly observed protoplanetary disks, brown dwarfs, intense and turbulent motions of the gas, and the photo-ionizing effects of massive nearby stars in the nebula.

The red hue is a result of the Hα recombination line radiation at a wavelength of 656.3 nm. This means that as high energy hydrogen electrons fall back into a lower orbit a red photon is emmitted.

PixInsight Processing -

-> Blink - remove bad frames

-> SubframeSelector - analyse frames for FWHM, # of stars, Ecentricity etc

-> ImageCalibration - use calibration frames to help remove fixed patterns etc

-> CosmeticCorrection - fix hot and cold pixels

-> Debayer - fix the colors before allignment

-> StarAllignment - registration to align the images.

-> LocalNormalization - normalize the images to reduce gradients

-> ImageIntegration - combine all the images into one !

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-> DynamicCrop - get rid of overlapping around edges

-> Even R,G,B colors -

ChannelExtraction - separate Red, Green and Blue channels

LinearFit - make all three channels the same intensity

ChannelCombination - Put the channels back together

-> AutomaticBackgroundExtractor - reduce unwanted colors in background

-> SCNR - get rid of unwanted green in image

-> BackgroundNeutralization - equalizes the average red, green and blue components

-> ColorCalibration - calibrate colors based on a neutral background

-> Create two masks, 1=luminance mask, 2=further stretching of 1

-> MultiscaleLinearTransform - denoise using mask 1

-> ACDNR - further denoise if needed

-> Stretch using ScreenTransferFunction and HistogramTransformation

-> HDRMultiscaleTransform - using mask 2

-> CurvesTransformation (mask 2)- luminance, saturate, RGB/K

-> LocalHistogramEqualization (mask 2) - bring out structures

-> UnsharpMask (mask 1) - give edges more contrast

-> StarMask - reduce overpowering stars as needed