An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



Number of Results: 11 Search : east
xâvar (#)

Fr.: est   

The point on the → celestial horizon 90° → clockwise from the → north point. The point where the Sun rises at the → equinoxes.

O.E. east, from P.Gmc. *aus-to-, *austra- "east, toward the sunrise" (cf. Du. oost, Ger. Ost, O.N. austr "from the east"), from PIE *aus- "dawn" (cf. Av. uš-, ušah- "dawn," Skt. usas-, usah- "dawn," Gk. aurion "morning," Lith. auszra "dawn," L. aurora "dawn," auster "south").

Xâvar "east," originally "west," from Mid.Pers. *xvar barân "where the Sun is led," from xvar "sun" (Av. hū-, hvar- "sun", cf. Skt. surya-, Gk. helios, L. sol, O.H.G. sunna, Ger. Sonne, E. sun; PIE base *sawel- "sun") + barân, pr.p. of bar-, bordan "to carry, lead" (Mid.Pers. burdan, O.Pers./Av. bar- "to bear, carry," barəθre "to bear (infinitive)," Skt. bharati "he carries," Gk. pherein, L. fero "to carry;" PIE base *bher- "to carry") + time and place suffix -ân.

xâvari (#)

Fr.: est, de l'est, oriental   

Lying toward or situated in the east.

From → east + -ern an adjective suffix occurring with names of directions.

Xâvari from xâvar, → east, + -i adj. suffix.

eastern elongation
  درازش ِ خاوری   
derâzeš-e xâvari

Fr.: élongation est   

The position of a planet when it can be seen in the western sky just after sunset.

eastern; → elongation.

greatest eastern elongation
  بزرگترین درازش ِ خاوری   
bozorgtarin derâzeš-e xâvari

Fr.: plus grande élongation est   

The Greatest → elongation of an inferior planet occurring after sunset.

Superlative of → great; → eastern; → elongation.

  کوچکترین، کمترین   
kucektarin, kamtarin

Fr.: moindre, plus petit   

Smallest in size, amount, degree, etc.

From M.E. leest(e), O.E. læst, læsest "smallest" (superlative of læs "smaller, less").

Kucaktarin, kamtarin, superlatives of kucak and kam, → small.

least common multiplier (LCM)
  کوچکترین بستاگر ِ همدار   
kucektarin bastâgar-e hamdâr

Fr.: plus petit commun multiple   

Of two or more → integers, the smallest positive number that is divisible by those integers without a remainder.

least; → common; → multiplier.

least squares
  کوچکترین چاروش‌ها   
kucaktarin cârušhâ

Fr.: moindres carrés   

Any statistical procedure that involves minimizing the sum of squared differences.

least; → square.

least-squares deconvolution (LSD)
  واهماگیش ِ کمترین چاروشها   
vâhamâgiš-e kucaktarin cârušhâ

Fr.: déconvolution des moindres carrés   

A → cross correlation technique for computing average profiles from thousands of → spectral lines simultaneously. The technique, first introduced by Donati et al. (1997, MNRAS 291,658), is based on several assumptions: additive → line profiles, wavelength independent → limb darkening, self-similar local profile shape, and weak → magnetic fields. Thus, unpolarized/polarized stellar spectra can indeed be seen as a line pattern → convolved with an average line profile. In this context, extracting this average line profile amounts to a linear → deconvolution problem. The method treats it as a matrix problem and look for the → least squares solution. In practice, LSD is very similar to most other cross-correlation techniques, though slightly more sophisticated in the sense that it cleans the cross-correlation profile from the autocorrelation profile of the line pattern. The technique is used to investigate the physical processes that take place in stellar atmospheres and that affect all spectral line profiles in a similar way. This includes the study of line profile variations (LPV) caused by orbital motion of the star and/or stellar surface inhomogeneities, for example. However, its widest application nowadays is the detection of weak magnetic fields in stars over the entire → H-R diagram based on → Stokes parameter V (→ circular polarization) observations (see also Tkachenko et al., 2013, A&A 560, A37 and references therein).

least; → square; → deconvolution.

least-squares fit
  سز ِ کوچکترین چاروش‌ها   
saz-e kucaktarin cârušhâ

Fr.: ajustement moindres carrées   

A fit through data points using least squares.

least squares; → fit.

method of least squares
  روش ِ کمترین چاروش‌ها   
raveš-e kamtarin cârušhâ

Fr.: méthode des moindres carrés   

A method of fitting a curve to data points so as to minimize the sum of the squares of the distances of the points from the curve.

method; → least squares.

principle of least action
  پَروز ِ کمترین ژیرش، ~ ~ کنش   
parvaz-e kamtarin žireš, ~ ~ koneš

Fr.: principe de moindre action   

The principle that, for a system whose total mechanical energy is conserved, the path to be taken for the system from one configuration to another is the one whose action has the least value relative to all other possible paths and from the same configurations. Also called Maupertuis' principle, least-action principle.

principle; → least; → action.