Nadir is employed during remote sensing of the atmosphere, as well as when an astronaut faces the Earth while performing a spacewalk. The term nadir can also be used to represent the lowest point reached by a celestial body during its apparent orbit around a given point of observation. This can be used to describe the location of the Sun, but it is only technically accurate for one latitude at a time and only possible at the low latitudes. The sun is said to be at the nadir at a location when it is at the zenith at the location's antipode
Nadir and the sun is 90 degrees below the horizon. This only occurs between the Tropic of Cancer and Tropic of Capricorn at solar midnight. The tropic circles experience this once a year on their winter solstices and all other tropical regions experience this twice. The term nadir also applies to video footage produced for use in Virtual Reality aka 360º video. Cameras capable of capturing spherical footage are generally mounted on a tripod or extension boom that sits directly below and perpendicular to the horizontal plane of the camera lenses (when using two, 180º FOV lenses). In the case of