1. A computer-implemented method comprising: identifying, by one or more computing devices, a position of a feature in imagery based on the visual similarity of the feature to a celestial object; determining, by the one or more computing devices, an elevation value associated with the elevation angle of the celestial object based on the position of the feature within the imagery; determining, by the one or more computing devices, an azimuth value associated with the azimuth of the celestial object based on the likelihood of the celestial object being at a particular azimuth at the elevation angle over a plurality of days; and determining, by the one or more computing devices, a compass orientation of the imagery based on the azimuth value.