Any reproduction of an object produced by means of focusing light, sound, electron radiation or other emanations coming from the object or reflected by another object. Its wavelength is between light and radio waves, in the range from about 0.75 micrometers to 1000 micrometers. All the physical, recognizable, naturally formed features of land, having a characteristic shape. A device that sends out light waves in a very narrow and strong beam of a specific, coordinated wavelength. Latitude is measured in degrees, minutes and seconds of arc.
Longitude is measured in degrees, minutes and seconds of arc.
A unit of wavelength equal to one millionth of a meter. The act or power of seeing or noticing and writing down some fact. The situation of two celestial bodies having celestial longitudes or sidereal hour angles differing by 180 degrees. The path followed by a planet, a satellite, or a star around a more massive body in its gravity induced motion. Surface feature on Mars, evidence that liquid water once existed there in great quantity.