Observation of the shadows of the Moon and Sun using 100 TeV cosmic rays

The Chicago Air Shower Array has imaged the shadows of the Moon and Sun and measured the angular diameter of the Moon with cosmic rays having energies above about 100 TeV. The shadow of the Sun shows effects attributed to the curvature of cosmic rays by the solar magnetic field. This study verifies that our direction reconstruction has no serious systematic errors, and provides a measure of the angular resolution of the array.