A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Robert VanderPol II
Date: 2019 May 14, 15:51 -0700
If you are touching limbs then which ever limb you are looking at in the index mirror is also the limb you are looking at in the horizon mirror. The artificial horizon inverts the horizon image. If the scope inverts the index image it will also invert the horizon image at the same time.
If you are trying to line up the centers of the suns images then you will have a mismatch of limbs but then you won't be worring about semidiameter then either.