Other important navigation tools include: the sextant, the astrolabe, the diptych, GPS devices.

FORBES: No. 3 The Compass

As the terrains fly by beneath us, however, we begin to sense that Kaplan has laid out a vast, Ptolemaic astrolabe, with cycles and epicycles and turning inner orbits and mechanics of the sky, elaborating everything and explaining little.

NEWYORKER: Faces, Places, Spaces