I've been customizing milhud and I can't get rid of the disc shadow in the upper half of the scanner.
It's there on the original milhud scanner too, but not on the default scanner. It's on all ships that I've tried as well.
Examing the milhud.png in PaintSHopPro doesn't show anything.
The only image I can find that's similar is Resources\Textures\target_metal.png. Even deleting this file doesn't remove the shadow.
@tomsk
You're using an older version of Milhud made for Oolite 1.65. Oolite 1.65 had an odd bug that shifted the co-ords of hud background images, and us hud designers compensated for that. Oolite 1.7x fixed the bug, which resulted in the compensated hud backgrounds being offcenter, which is what you're seeing.
The purpose of the 'disk' is to improve contrast in the gunsight area, and it's supposed to be aligned with the gunsight.