River Lune painted by J. M. W. Turner. The M6 motorway crosses the Lune near Tebay and Halton-on-Lune; in 2015 it was joined by the Heysham to M6 Link Road. The Ingleton branch line, a railway operational between 1861 and 1967, followed the Lue between Tebay and Kirkby Lonsdale, crossing the river twice on viaducts which still stand. Near the end of the non-tidal reach of the river stands the Lune Aqueduct, which carries the Lancaster Canal. The Lune is now tidal only below Skerton Weir in Lancaster. Four bridges in close proximity cross the estuary in Lancaster: Skerton Bridge (road), Greyhound
Spherical lune two polar opposite points. Common examples of great circles are lines of longitude ("meridians") on a sphere, which meet at the north and south poles. A spherical lune has two planes of symmetry. It can be bisected into two lunes of half the angle, or it can be bisected by an equatorial line into two right spherical triangles. The surface area of a spherical lune is 2θ "R", where "R" is the radius of the sphere and θ is the dihedral angle in radians between the two half great circles. When this angle equals 2π radians (360°) — i.e., when