Nautical mile favour of the international nautical mile in 1954. The Imperial nautical mile, often called an Admiralty mile, or more correctly, an Admiralty measured mile, was defined by its relation to the Admiralty knot, 6,080 imperial feet per hour, so 1 imperial nautical mile is about 1,853.181 metres. It was abandoned in 1970 and, legally, references to the obsolete unit are now converted to 1,853 metres. Despite the existence of precise modern definitions, in the early 21st century the old definitions are still in use. The Royal Yachting Association says in its manual for day skippers: "1 (minute) of Latitude =
Celestial equator south), the celestial equator tilts towards the opposite horizon. The celestial equator is defined to be infinitely distant (since it is on the celestial sphere); thus, the ends of the semicircle always intersect the horizon due east and due west, regardless of the observer's position on Earth. (At the poles, the celestial equator coincides with the astronomical horizon.) At all latitudes, the celestial equator is a uniform arc or circle because the observer is only finitely far from the plane of the celestial equator, but infinitely far from the celestial equator itself. Astronomical objects near the celestial equator appear above