 The larger complex wheels are capable of tracking several different cosmic cycles, including the precession of the equinoxes, the Moon's phases, lunar and solar eclipse cycles, and planets' orbital cycles.These astronomical wheels mirror the north ecliptic polar region of the sky and are useful as celestial grids to track changes over millennial time periods.Astronomer John Eddy investigated the Big Horn Medicine Wheel's structure in 1972 and made a number of important discoveries, publishing his findings in "Astronomical Alignment of the Big Horn Medicine Wheel," Science 184 (1974)