Hun Kal (crater)

Mercury crater data


caption=Hun Kal is indicated by an arrow.
latitude=0.5
N_or_S=S
longitude=20
E_or_W=W
diameter=1.5 km
eponym='20' in the Mayan language

Hun Kal is a small crater on Mercury that serves as the reference point for the planet's system of longitude. The longitude of Hun Kal's center is defined as being 20° W, thus establishing the planet's prime meridian.

Hun Kal was chosen as a reference point since the actual prime meridian was in shadow when Mariner 10 photographed the region, hiding any features near 0° longitude from view.