The sun is spherical, yet the image will appear mostly flat. By leveraging PixInsight Curves Transformation, additional shading can be added to the edges to give the sun a more spherical appearance.
Improve Shading
PixInsight Curves Transformation provides an easy approach to modify the shading of the sun. Within Curves Transformation, create a gentle S-Curve with the RGB/K channel.
The saturation is minor so you can apply it multiple times until you find the perfect spot for your image.
Find a level that is pleasing. In this example, the first appeared adequate while the second looked too agressive. Again, this is a personal preference.
What’s Next
This file becomes the new enhanced luminance image. Please refer back to the solar image workflow for the next step in the image processing workflow.