# Angular+distance

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**Zenith distance**— Distance Dis tance, n. [F. distance, L. distantia.] 1. The space between two objects; the length of a line, especially the shortest line joining two points or things that are separate; measure of separation in place. [1913 Webster] Every particle …42

**angular momentum**— noun the product of the momentum of a rotating body and its distance from the axis of rotation any rotating body has an angular momentum about its center of mass angular momentum makes the world go round • Hypernyms: ↑momentum …43

**Angular vibration**— In optics the action of tilting an image forming system is to smear the image. Such aberration is constant for all distances to the subject.The opposite is linear vibration, also known as parallel vibration, where the aberration close to the… …44

**zenith distance**— noun or zenith angle : the angular distance of a celestial object from the zenith measured by the arc of a vertical circle intercepted between the object and the zenith : the complement of the altitude * * * Astron. the angular distance from the… …45

**Polar distance**— Polar Po lar, a. [Cf. F. polaire. See {Pole} of the earth.] 1. Of or pertaining to one of the poles of the earth, or of a sphere; situated near, or proceeding from, one of the poles; as, polar regions; polar seas; polar winds. [1913 Webster] 2.… …46

**Lunar distance**— Lunar Lu nar (l[=u] n[ e]r), a. [L. lunaris, fr. luna the moon. See {Luna}, and cf. {Lunary}.] 1. Of or pertaining to the moon; as, lunar observations. [1913 Webster] 2. Resembling the moon; orbed. Dryden. [1913 Webster] 3. Measured by the… …47

**Polar distance (astronomy)**— Polar distance (PD) is an astronomical term associated with the celestial equatorial coordinate system Σ(α, δ) and it is an angular distance of a celestial object on its meridian measured from the celestial pole, similar as declination (dec, δ)… …48

**polar distance**— The angular distance from a celestial pole. The polar distance of any celestial body is equal to 90° minus the declination of the body …49

**zenith distance**— Astron. the angular distance from the zenith of a point on the celestial sphere to the sphere, measured along a great circle that is perpendicular to the horizon; the complement of the altitude. [1695 1705] * * * …50

**zenith distance**— The angular distance through the arc of a vertical circle between the zenith and a point on the celestial sphere, measured from the zenith through 90°, for bodies above the horizon. Also known as co altitude …