From, away, off.
M.E., from O.Fr., from L. ab "from, away from, out of, with" Gk.
1) To leave completely and finally; forsake utterly; desert.
M.E. abando(u)nen, from M.Fr. abandoner, from O.Fr. abandoner from adverbial phrase à bandon "at will, at discretion," from à "at, to," → ad-, + bandon "power, jurisdiction," from L. bannum "proclamation."
Râcidan, related to Pers. parhêz, parhiz "to keep away from, abstain, avoid," gurêz, goriz "to flee, run away;" Av. raēc- "to leave, let;" → heritage.
Fr.: nombre d'Abbe
The reciprocal of the → dispersive power of a substance. Also known as constringence.
Abbe sine condition
butâr-e sinus-e Abbe
Fr.: condition des sinus d'Abbe
In → geometric optics, a condition for eliminating → spherical aberration and → coma in an → optical system. It is expressed by the relationship: sin u'/U' = sin u/U, where u and U are the angles, relative to the → optical axis, of any two rays as they leave the object, and u' and U' are the angles of the same rays where they reach the image plane. A system which satisfies the sine condition is called → aplanatic.
Fr.: sphère d'Abbe
Fr.: théorème d'Abel
1) If a → power series → converges
for some nonzero value
x0, then it converges absolutely for any value of x, for
which |x| < |x0|.
Named after the Norwegian mathematician Niels Henrik Abel (1802-1829); → theorem.
Fr.: catalogue Abell
A catalog of 4073 rich → galaxy clusters grouped by constellation and by catalog number. Published first in 1958, it contained the clusters visible from the northern hemisphere. A supplement for the southern hemisphere survey was published in 1988.
George O. Abell (1927-1983), American astronomer; → catalog.
Fr.: s'égarer, dévier
Diverge or deviate from the straight path; produce → aberration.
Aberrate, from aberrare "go astray," from ab- "away" + errare "to wander."
Birâhidan, from birâh "a devious path; a wanderer, who deviates, errs," from bi- "without" + râh "way".
1) An imperfection in the imaging properties of a → lens
or → mirror.
The main aberrations are → chromatic aberration,
→ spherical aberration, → coma,
→ astigmatism, → distortion,
and → field curvature.
Aberration, from L. aberrationem, from aberrare "go astray," → aberrate.
Birâheš, from birâidan, → aberrate.
Fr.: angle d'aberration
The angle tilt required by the → stellar aberration phenomenon in order that a moving telescope points directly to a star.
Fr.: constante d'aberration
Same as → constant of aberration.
aberration of light
Fr.: aberration de la lumière
aberration of starlight
birâheš-e nur-e setâré
Fr.: aberration de la lumière d'étoile
An apparent displacement in the observed position of a star. It is a result of the finite speed of light combined with the relative motion of the Earth through space. Suppose that you walk through a vertically falling rain with an umbrella over your head. The faster you walk, the further you must lower the umbrella in front of yourself to prevent the rain from striking your face. For starlight to enter a telescope, a similar phenomenon must occur, because the Earth is in motion. The telescope must be tilted in the direction of motion by an angle: tan θ =(v/c), where v the Earth velocity and c the speed of light. The aberration of starlight was discovered by the English astronomer James Bradley (1693-1762) in 1729 by observing → Gamma Draconis. The tilt angle is θ = 20''.50, from which the Earth's orbital speed, 29.80 km s-1, can be deduced, using the above equation. See also → annual aberration; → diurnal aberration; → secular aberration. → Special relativity modifies the classical formula for aberration, predicting results which differ substantially from those of classical physics for objects moving at a substantial fraction of the speed of light; → relativistic aberration.
Fr.: orbite d'aberration
The apparent path described by a star on the → celestial sphere due → annual aberration. A star at the → ecliptic pole is seen to move around a circle of angular radius about 20".50, once a year. A star on the → ecliptic oscillates to and fro along a line of angular half-length 20".50. At an intermediate → celestial latitude, β, the aberration orbit is an ellipse, with semi-major axis 20".50 and semi-minor axis (20".50) sin β.
Of or pertaining to → aberration.
aberrational day number
šomâre-ye ruz-e birâheši
Fr.: nombre de jours d'aberration
A → Besselian day number denoted by C or D.
Fr.: ellipse d'aberration
L. ablatio, ablation, from ablatus, from ab- "away" + latus "carried."
Farsâb from far-, prefix denoting "abundance, excess" + sâb present stem of sâbidan "to rub, wear out," variants sâyidan, pasâvidan "to touch," Khotanese sauy- "to rub," Sogdian ps'w- "to touch," Proto-Iranian *sau- "to rub."
M.L. anormalis, blend of L.L. abnormis "deviating from a rule," from ab- "off, away from" + L. norma "rule."
Bihanjâr, from Pers. bi- "without" + Pers. hanjâr "rule, habit, law, staright road."
1) To terminate a procedure before it has finished naturally.
From L. abortus, p.p. of aboriri "to miscarry" (a child) from → ab- "from, away, off," + oriri "to rise, be born;" cf. Pers. rasidan "to attain; to arrive" (Mid.Pers. rasidan "to arrive, to mature;" O.Pers./Av. rasa- present stem of ar- "to move, go or come toward;" Skt. ar-, rcchati "reaches;" Gk. erkhomai "to go, to reach").
Fagânidan, from fagâné "abortion", related to fegandan, fekandan, afkandan "to throw, to cast away;" Mid.Pers. abgandan "to throw;" O.Pers. avakan- "to throw, place on," from Proto-Iranian *kan- "to throw, place, put."