I thought the group might be interested in a fix I have evolved for limb darkening/bright spots in solar images.
Solar scopes can often produce bright areas or limb darkening, especially with wide angle views of the whole solar disc. This method uses GIMP, but Photoshop will be similar.
First you create a blurred version of the original using a gaussian blur or similar. This image will be darker in the areas you want to increase the gain. You then open this and the original as layers. You then set the mode of the blurred layer to “divide”, and adjust the “curves” on this layer until you get a satifactory image, and then merge down.
I know this might sound like gobbledygook for the non-image processors, but it really isn’t that hard!
Below is the image I posted yesterday, and the compensated one.