Got this with my new camera thru my C8. pretty happy except with the top right edge of the planet. Don’t know what’s going on there, if it is a capture problem, stacking problem or processing problem but it appears on all my Mars images
Nice image there Nick, as Dunk said above, the "rind" is a diffraction effect enhanced by sharpening. There are a number of ways to reduce the appearance (smoothing, healing tool, layer a less sharpened version on top of the more sharpened version on the edge), but you cannot really get rid of it.
