# Angular+distance

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**Great-circle distance**— The great circle distance is the shortest distance between any two points on the surface of a sphere measured along a path on the surface of the sphere (as opposed to going through the sphere s interior). Because spherical geometry is rather… …62

**distancia angular**— Eng. Angle distance Ángulo formado a nivel del ojo por dos líneas trazadas desde el ojo hasta dos objetos …63

**SN 1054**— Supernova SN 1054 The Crab Nebula, remnant of SN 1054. Credit: NASA/ESA. Observation data (Epoch ?) Supernova type …64

**Minute of arc**— This article is about geometry. For firearms terminology, see Minute of Angle. A minute of arc, arcminute, or minute of angle (MOA), is a unit of angular measurement equal to one sixtieth (1⁄60) of one degree. In turn, a second of arc or… …65

**Gravitational microlensing**— Gravitational Lensing Formalism Strong lensing …66

**Orbit of the Moon**— Not to be confused with Lunar orbit in the sense of a selenocentric orbit, that is, an orbit around the Moon The Moon completes its orbit around the Earth in approximately 27.3 days (a sidereal month). The Earth and Moon orbit about their… …67

**Diffraction topography**— (short: topography ) is an X ray imaging technique based on Bragg diffraction. Diffraction topographic images ( topographs ) record the intensity profile of a beam of X rays (or, sometimes, neutrons) diffracted by a crystal. A topograph thus… …68

**celestial mechanics**— the branch of astronomy that deals with the application of the laws of dynamics and Newton s law of gravitation to the motions of heavenly bodies. [1815 25] * * * Branch of astronomy that deals with the mathematical theory of the motions of… …69

**parallax**— parallactic /par euh lak tik/, adj. parallactically, adv. /par euh laks /, n. 1. the apparent displacement of an observed object due to a change in the position of the observer. 2. Astron. the apparent angular displacement of a celestial body due …70

**Messier 87**— Virgo A The Messier 87 galaxy. Observation data Epoch J2000 Constellation Virgo Right ascension …