An eyepiece provides an inner-view perspective of the far-side surface of Earth. Swiveling in two axes allows the device to point to all parts of the globe with graphics and text superimposed — great circle path to the distant location, meridians & parallels, distances, and dynamic text describing the field of view.

A bit like those coin-operated telescopes and binoculars found on vista-points overlooking cities. But this could be installed anywhere, and the vista would be much more vast.