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M 97 - Owl Nebula

by Alejandro Tombolini

Introduction

Image of Andres Pozo publicated in PixInsight Forum. Date: March 2014.

Processing

First crop the lines at the edges of the image.

M 97

A fist very smooth noise reduction using GREYCStoration tool. (Decrese Precision and Amplitude)

M 97

Now AutomaticBackgroundExtractor only decreasing a little Deviation to avoid samples near stars.

M 97

DynamicPSF tool to generate the PSF to be used in Deconvolution tool. I placed arround 15 samples near de center of the image.

M 97

Deconvolution adjusting a little Global dark in Deringing protection to avoid dark circles in stars and Noise threshold in Wavelet Regularization to avoid an increase of noise in the background.

M 97

Transfer the ScreenTransferFunction to HistogramTransformation tool and apply it.

M 97

HDRMultiscaleTransform to give a little contrast in the nebulae.

M 97

Now I will build a mask to protect either the nebulae when working over the background or the background when working over the nebulae.

First a range mask using RangeSelection tool.

M 97

Multiply the image and the rangemask.

M 97

Protecting the background apply LocalHistogramEqualization to give contrast in the nebulae.

M 97

UnsharpMask to the nebulae.

M 97

As the noise has increased apply TGVDenoise to reduce it.

M 97

Now inverting the mask, noise reduction to background using ATrousWaveletTransform.

M 97

The noise could be reduced a little more, but I think that is ok. Protecting the nebulae apply Gamma Stretch tool to decrease the bright of the background.

M 97

Final image.

M 97

Last Update: 29/03/2014 00:58 UT

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