Filar micrometer
Micrometer Mi*crom"e*ter, n. [Micro- + -meter: cf. F. microm[`e]tre.] An instrument, used with a telescope or microscope, for measuring minute distances, or the apparent diameters of objects which subtend minute angles. The measurement given directly is that of the image of the object formed at the focus of the object glass. [1913 Webster]

{Circular micrometer}, or {Ring micrometer}, a metallic ring fixed in the focus of the object glass of a telescope, and used to determine differences of right ascension and declination between stars by observations of the times at which the stars cross the inner or outer periphery of the ring.

{Double image micrometer}, a micrometer in which two images of an object are formed in the field, usually by the two halves of a bisected lens which are movable along their line of section by a screw, and distances are determined by the number of screw revolutions necessary to bring the points to be measured into optical coincidence. When the two images are formed by a bisected object glass, it is called a divided-object-glass micrometer, and when the instrument is large and equatorially mounted, it is known as a heliometer.

{Double refraction micrometer}, a species of double image micrometer, in which the two images are formed by the double refraction of rock crystal.

{Filar micrometer}, or {Bifilar micrometer}. See under {Bifilar}.

{Micrometer caliper} or {Micrometer gauge} (Mech.), a caliper or gauge with a micrometer screw, for measuring dimensions with great accuracy.

{Micrometer head}, the head of a micrometer screw.

{Micrometer microscope}, a compound microscope combined with a filar micrometer, used chiefly for reading and subdividing the divisions of large astronomical and geodetical instruments.

{Micrometer screw}, a screw with a graduated head used in some forms of micrometers; turning the head one full revolution advances the position of the tip of the screw only by a little.

{Position micrometer}. See under {Position}.

{Scale micrometer}, or {Linear micrometer}, a minute and very delicately graduated scale of equal parts used in the field of a telescope or microscope, for measuring distances by direct comparison. [1913 Webster]


The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • filar micrometer — n an instrument for accurately measuring small distances or angles that usu. consists of two parallel fine platinum wires mounted in the focal plane of a microscope or telescope with one wire being fixed and the other movable by means of a finely …   Medical dictionary

  • Filar micrometer — A filar micrometer is a device used in astronomical telescopes for precision measurements. The word filar derives from Latin filum , a thread. It refers to the fine threads or wires used in the device. Construction and useThe filar micrometer… …   Wikipedia

  • filar micrometer — Bifilar Bi*fi lar, a. [Pref. bi + filar.] Two threaded; involving the use of two threads; as, bifilar suspension; a bifilar balance. [1913 Webster] {Bifilar micrometer} (often called {a bifilar}), an instrument form measuring minute distances or… …   The Collaborative International Dictionary of English

  • filar micrometer — siūlinis mikrometras statusas T sritis Standartizacija ir metrologija apibrėžtis Mikrometras, kuriame yra rėmelis su matavimo siūlais. Naudojamas mažiems atstumams matuoti teleskopo židinio plokštumoje. atitikmenys: angl. crossbar micrometer;… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • filar micrometer — siūlinis mikrometras statusas T sritis fizika atitikmenys: angl. crossbar micrometer; filar micrometer vok. Fadenmikrometer, n; Kreuzfadenmikrometer, n rus. нитяной микрометр, m pranc. micromètre à fils, m; micromètre à réticule, m; micromètre… …   Fizikos terminų žodynas

  • filar micrometer — noun : an instrument for accurately measuring small distances or angles usually consisting of two parallel fine platinum wires mounted in the focal plane of a microscope or telescope, one wire being fixed and the other movable by means of a… …   Useful english dictionary

  • Micrometer — Mi*crom e*ter, n. [Micro + meter: cf. F. microm[ e]tre.] An instrument, used with a telescope or microscope, for measuring minute distances, or the apparent diameters of objects which subtend minute angles. The measurement given directly is that… …   The Collaborative International Dictionary of English

  • Micrometer caliper — Micrometer Mi*crom e*ter, n. [Micro + meter: cf. F. microm[ e]tre.] An instrument, used with a telescope or microscope, for measuring minute distances, or the apparent diameters of objects which subtend minute angles. The measurement given… …   The Collaborative International Dictionary of English

  • Micrometer gauge — Micrometer Mi*crom e*ter, n. [Micro + meter: cf. F. microm[ e]tre.] An instrument, used with a telescope or microscope, for measuring minute distances, or the apparent diameters of objects which subtend minute angles. The measurement given… …   The Collaborative International Dictionary of English

  • Micrometer head — Micrometer Mi*crom e*ter, n. [Micro + meter: cf. F. microm[ e]tre.] An instrument, used with a telescope or microscope, for measuring minute distances, or the apparent diameters of objects which subtend minute angles. The measurement given… …   The Collaborative International Dictionary of English

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