Image of the Month - September 2019

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Guy Wells via Facebook

Guy kindly shared his process for creating this beautiful image of the galaxy M74...

To start:

  • For the integration and processing I used PixInsight
  • I combined the RGB image as usual, except I used the V files to add to the G channel


  • I aligned each channel and stacked them
  • I then stacked the 3 channels into a single colour image
  • Next I cropped the image to remove artifacts present on the edge of the image
  • I then used DBE (Dynamic Background Extraction) to remove the background gradient
  • Next is colour calibration and then the image is then stretched
  • I decided to do a HDR Multiscale Transformation to reveal some of the inner structure that would otherwise be overexposed

Noise reduction:

  • Setting the blackpoint of the image (not too harshly)
  • I used a masked saturation boost to enhance the colour
  • Finally I removed green from the image as that doesn't really look that natural in this case


  • I balanced the colour a little and sharpened the image a little too

This process took Guy around 15-20 minutes.


M74 by Guy Wells