A mathematical operation that allows to restore the original input signal, such as an astronomical image or spectrum, to its state before being affected by the → atmospheric turbulence and the → transfer function of the instrument. → convolution.
Fr.: logiciel de déconvolution, algorithme ~ ~
An algorithm used to improve the resolution of an image particularly when the convolving function is well defined. Also called deconvolution code.
Verbal form of → deconvolution.
1) To separate or detach; to cause to become disconnected or divergent.
Cosmology: In the early history of the Universe, separation of matter and radiation due to their non-interaction. At a redshift of 1000, that is about 400,000 years after the Big Bang, the temperature would have cooled to the point (4000 degrees Kelvin) where electrons and nuclei can recombine and form neutral hydrogen atoms. Since atoms do not scatter the radiation appreciably, free electrons were lacking, and the Universe became transparent to radiation. Same as → recombination. See also → decoupling era.
dowrân-e vâjafsari, ~ vâjofteš
Fr.: époque du découplage
1) kâstan (#), kâhidan (#); 2) kâheš (#)
Fr.: 1) décroitre; 2) décroissance
1) (v.tr.) To cause to diminish, to make less. (v.intr.) To diminish or
lessen in extent, quantity, power, etc.
Kâstan, kâh-, from Mid.Pers. kâhitan, kâstan, kâhênitan "to decrease, diminish, lessen," Av. kasu- "small, little" (Mod.Pers. keh), Proto-Iranian *kas- "to be small, diminish, lessen;" kâheš verbal noun from kâhidan.
1) The amount lost in the process of decreasing.
L decrementum, from decre(tus), → decrease + -mentum noun suffix -ment.
Kâheh, from kâh- present stem of kâhidan, → decrease + noun suffix -é.
A physical process that is contrary to accretion, referring to the outward direction of the mass flow from a star to its environment.
Fr.: disque de décrétion
A disk that would form around a star when the star injects matter into a close orbit. This is in contrast to an → accretion disk, which transfers matter from outside to the star. The mass gets injected into the decretion disk by a not yet well-known mechanism, most probably a combination of → non-radial pulsation, fast rotation, and possibly small-scale → magnetic fields. See also → viscous decretion disk.
To derive as a conclusion from facts or premises.
L. deducere "to lead down, derive," from → de- "down" + ducere "to lead."
Foruhâxtan, foruhâzidan, from foru- "down," → de- + Mid.Pers. hâxtan, hâzidan "to lead, guide, persuade," Av. hak-, hacaiti "to attach oneself to, to join," cf. Skt. sacate "accompanies, follows," Gk. hepesthai "to follow," L. sequi "to follow;" PIE *sekw- "to follow."
1) The act or process of deducting; something that is or may be deduced.
Verbal noun from → deduce.
Of or relating to → deduction.
Fr.: raisonnement déductif
1) žarf (#), gowd (#); 2) žarfnâ (#)
Fr.: 1) profond; 2) profondeur
1a) General: Extending well inward from an outer surface or back from an edge.
O.E. deop, from P.Gmc. *deupaz, from PIE *d(e)u- "deep, hollow."
Žarf "deep;" variants Gilaki jalf, julf, jal; Tabari
jol, jal, jul; Baluci jahl, johl; Kermâni jarr "deep;"
Mid.Pers. zufr; Av. jafra- "deep."
osneheš-e žarf, nurdâd-e ~
Fr.: pose profonde
An exposure in which the detector shutter remains open for a relatively long time in order to bring out the weaker features of the observed object. In practice a deep exposure with a CCD detector is usually obtained from co-addition of shorter exposures.
Fr.: champ profond
An area on the sky whose image is obtained with a deep exposure, such as → Hubble Deep Field.
vine-ye žarf, tasvir-e ~
Fr.: image profonde
An image obtained using a deep exposure to reveal the weak features of the object.