Airy-0

Crater on Mars whose location defines the position of the prime meridian

Airy-0 is a crater inside the larger Airy Crater on Mars, whose location historically defined the Martian prime meridian. It is about 0.5 km (0.3 mile) across and lies within the dark region Sinus Meridiani, one of the early albedo features to be identified on Mars. In 2018, the IAU Working Group on Cartographic Coordinates and Rotational Elements recommended setting the longitude of the Viking 1 lander as the reference line. This definition maintains the position of the center of Airy-0 at 0° longitude, within the tolerance of current cartographic uncertainties.

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