Focal distance of a telescope
Focal Fo"cal, a. [Cf. F. focal. See {Focus}.] Belonging to,or concerning, a focus; as, a focal point. [1913 Webster]

{Focal distance, or length, of a lens or mirror} (Opt.), the distance of the focus from the surface of the lens or mirror, or more exactly, in the case of a lens, from its optical center.

{Focal distance of a telescope}, the distance of the image of an object from the object glass. [1913 Webster]


The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • Focal distance or length of a lens or mirror — Focal Fo cal, a. [Cf. F. focal. See {Focus}.] Belonging to,or concerning, a focus; as, a focal point. [1913 Webster] {Focal distance, or length, of a lens or mirror} (Opt.), the distance of the focus from the surface of the lens or mirror, or… …   The Collaborative International Dictionary of English

  • focal distance — noun the distance from a lens to its focus • Syn: ↑focal length • Hypernyms: ↑distance * * * focal distance noun Focal length • • • Main Entry: ↑focus * * * …   Useful english dictionary

  • Focal — Fo cal, a. [Cf. F. focal. See {Focus}.] Belonging to,or concerning, a focus; as, a focal point. [1913 Webster] {Focal distance, or length, of a lens or mirror} (Opt.), the distance of the focus from the surface of the lens or mirror, or more… …   The Collaborative International Dictionary of English

  • telescope — /tel euh skohp /, n., adj., v., telescoped, telescoping. n. 1. an optical instrument for making distant objects appear larger and therefore nearer. One of the two principal forms (refracting telescope) consists essentially of an objective lens… …   Universalium

  • Focal length — The focal length of an optical system is a measure of how strongly it converges (focuses) or diverges (diffuses) light. A system with a shorter focal length has greater optical power than one with a long focal length. Thin lens approximation For… …   Wikipedia

  • focal length — Optics. 1. the distance from a focal point of a lens or mirror to the corresponding principal plane. Symbol: f 2. the distance between an object lens and its corresponding focal plane in a telescope. Also called focal distance. [1745 55] * * * …   Universalium

  • focal length — /ˈfoʊkəl lɛŋθ / (say fohkuhl length) noun 1. (of a mirror or lens) the distance from the optical centre to the focal point. 2. (of a telescope) the distance between the object lens and its corresponding focal plane …   Australian English dictionary

  • focal length — noun the distance between the centre of a lens or curved mirror and its focus. ↘the equivalent distance in a compound lens or telescope …   English new terms dictionary

  • Télescope Chandra — Chandra (télescope spatial) Chandra Vue d artiste du télescope spatial Chandra Caractéristiques Organisation …   Wikipédia en Français

  • Télescope spatial Chandra — Chandra (télescope spatial) Chandra Vue d artiste du télescope spatial Chandra Caractéristiques Organisation …   Wikipédia en Français

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