Correcting Limb Darkening in Solar Images

So i have an image of the sun which I need to correct for limb darkening. As far as I am aware, I need to run a macro to adjust the pixel values as a function of the radius from the centre. I cannot find the best way to run this function on an image, or if I need to also run a macro to find the centre of the disk as well, as a reference point.

Any help greatly received

Hello @chrisphys,

Can you upload here any sample image so we can understand better what you’re trying to do?


Hi Sorry, image is attached. The images shows the intensity drops off towards the edge of the solar disk which is an effect due to the angle of viewing, as the intensity should be the same throughout the disk.

It has been suggested that I create a second image from the original with the background values at 0 and the solar values set as the multiplication factors needed for each pixel and use the image calculator to apply these to my own image.

The formula used for limb darkening correction is found here;

I have started constructing a macro to edit the pixel values based on their distance from the centre of the solar disk but I am getting stuck on the code needed.

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I see! If you post the macro you have so far, we can help you.