In celestial navigation, lunar distance is in the angle of the Moon's centre from the Sun or from the bright stars. It is measured using a sextant. Using the lunar distance and a nautical almanac it is possible to calculate the current time and thus the current longitude.

In astronomy, a lunar distance is the distance from Earth to the Moon. The average distance from Earth to the Moon is 384,403 kilometer (238,857 miles). High-precision measurements of the lunar distance are made with the help of lidar measurements of the round-trip times for light beams between lasers at Earth-based monitoring stations and retroreflectors placed on the Moon. (See Lunar Laser Ranging Experiment).

See also

• navigation
• geodesy