You could do secants rather than diameters. Just image the surface layers. Although even just the 5km or so to the horizon sounds like a scary amount of energy.

You could do secants rather than diameters. Just image the surface layers. Although even just the 5km or so to the horizon sounds like a scary amount of energy. How about neutrino imaging? (I thought I was joking, but... https://www.nature.com/articles/s41567-018-0319-1 https://www.nature.com/articles/s41567-018-0319-1)