To adjust or determine, by comparison with a standard, the response magnitude of a measuring instrument as a function of the input signal. For example, to determine line wavelengths in the spectrum of an astronomical object, or to graduate a hygrometer.
From M.Fr. calibre, via Sp. or It., from Ar. qalib "a mold, last," perhaps from Gk. kalopodion "a shoemaker's last," from kalon "wood" + podos gen. of pous "foot."
Kabizidan, verbal form of kabiz (varianats kaviz, kaviž, kafiz) "a measure for grain, a bushel," from Mid.Pers. kabiz "a grain measure," loaned in Arm. kapic "a grain measure," and in Gk. kapithe, as attested in Xenophon.
Fr.: étalonnage, calibration
1) The act or process of calibrating or the state of being calibrated.
Calibration, noun from → calibrate.
Kabizeš, noun from kabizidan, → calibrate.
Fr.: courbe d'étalonnage
An empirical curve obtained through appropriate exposures in order to determine the instrument's response. For example, a curve allowing the conversion of relative intensities of an observed object into absolute fluxes, or a curve relating the detector's pixel positions to wavelengths.
Fr.: erreur d'étalonnage
A systematic error in the constant values to be applied to a measuring instrument.
Fr.: pose d'étalonnage
An exposure obtained with an instrument mounted on the telescope using an artificial illuminating source in order to calibrate the instrument.
Fr.: lampe d'étalonnage
A lamp used for instrument calibration, such as an internal He-Ar arc for wavelength calibration or an external source of light placed in the telescope dome for flat-field exposures.
→ calibration; lamp, from O.Fr. lampe, L. lampas, from Gk. lampas "torch, lamp, light, meteor," from lampein "to shine."
Kabizeš, → calibration; lâmp, from Fr., as above.
A general term for certain reference astronomical sources that allow determining the characteristics (magnitude, distance, velocity, etc.) of other sources. → primary calibrators, → secondary calibrators.
Kabizandé, agent noun from kabizidan, → calibrate.
First Point of Libra
noqte-ye âqâz-e tarâzu (#)
Fr.: permier point de Balance
One of the two points on the celestial sphere where the ecliptic and the celestial equator crossed one another at → autumnal equinox several thousands years ago. Because of → precession, this equinoctial point no longer lies in Libra but in neighboring Virgo.
Fr.: calibration de flux
The → calibration of the flux received by a detector in terms of absolute units.
roxgard-e hendesi (#)
Fr.: libration géométrique
A lunar libration motion either in latitude resulting from the inclination of the Moon's orbit with respect to the ecliptic, or in longitude due to the elliptical shape of the Moon's orbit which causes a change in its aspect as seen from the Earth. → libration; → physical libration.
Fr.: calibration hélium-argon
A wavelength calibration of astronomical spectra using a helium-argon light source.
The Scales. An inconspicuous constellation in the southern hemisphere and a sign of the → Zodiac, at 15h 30m right ascension, 15° south declination. Abbreviation: Lib; genitive: Librae.
L. libra "balance," of obscure origin.
Tarâzu "balance, scales," Mid.Pers. tarâzên-, taraênidan "to weigh," Proto-Iranian *tarāz-, from *tarā- "balance, scale" (cf. Skt. tulā- "scales, balance, weight," from tul- "to weigh, make equal in weight, equal," tolayati "weighs, balances," L. tollere "to raise," Gk. talanton "balance, weight," Atlas "the Bearer" of Heaven," Lith. tiltas "bridge;" PIE base telə- "to lift, weigh") + Av. az- "to convey, conduct, drive," azaiti drives" (cf. Skt. aj- "to dive, sling," ájati "drives," ajirá- "agile, quick," Gk. agein "to lead, guide, drive, carry off," L. agere "to do, set in motion, drive," from PIE root *ag- "to drive, move," → act).
An effect caused by the apparent wobble of the Moon as it orbits the Earth. The Moon always keeps the same side toward the Earth, but due to libration, 59% of the Moon's surface can be seen over a period of time.
L. libration- "a balancing."
Roxgard, literally "turning the face," from rox, variant ru(y) "face, surface; aspect; appearance" (Mid.Pers. rôy, rôdh "face;" Av. raoδa- "growth," in plural form "appearance," from raod- "to grow, sprout, shoot;" cf. Skt. róha- "rising, height") + gard "turning, changing," from gardidan "to turn, to change" (Mid.Pers. vartitan; Av. varət- "to turn, revolve;" Skt. vrt- "to turn, roll," vartate "it turns round, rolls;" L. vertere "to turn;" O.H.G. werden "to become;" PIE base *wer- "to turn, bend").
kabizeš-e šidsanjik, ~ nursanjik
Fr.: calibration photométrique
A calibration which converts the measured relative magnitudes into an absolute photometry.
Fr.: libration physique
Fr.: calibrateur secondaire
An indicator of extragalactic distances that relies on → primary calibrators in our Galaxy. Secondary calibrators of the distance scale depend on statistical measures of the properties of a class of objects, such as the brightness of H II regions, globular clusters, red and blue stars, or the neutral hydrogen 21-cm line width or velocity dispersion (of spiral galaxies), etc. Same as secondary distance indicator.