An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1) The act or process of adapting.
2) The state of being adapted.

→ adapt.

Physiological process whereby the eye adjusts its sensitivity for different levels of illumination.

→ adaptation, → eye.

1) General: One that adapts.
An appliance for connecting objects of different sizes or designs in an apparatus.
2) Astro.: A device that allows an observing instrument (imaging camera, spectrograph) to be mounted on a focus (e.g. Cassegrain) of a telescope.

→ adapt + → -er.

Same as → adaptation.

→ adaptation.

1) Relating to or exhibiting adaptation.
2) Capable of adapting or of being adapted. → adaptive optics; → adaptive optics system; → extreme adaptive optics.

→ adapt; → -ive.

A type of → algorithm that dynamically achieves high → resolution in localized regions of multidimensional → numerical simulations. AMR provides a higher → accuracy solution at lower costs, through an automatically → optimal distribution of → grid points for the computation region. It relies on locally refined mesh or mesh patches to increase the resolution of an underlying coarse mesh only where needed. It can alleviate some of the complexities of the generation of high quality grid and reduce the number of → iterations of "trial-and-error" between the grid generation and solution required for tailoring the grid to the specification of a problem. Thus, it can offer orders of magnitude saving in computational and storage costs over an equivalent uniformly refined mesh. AMR was originally developed for → inviscid, → compressible flow (Berger et al., 1984, Adaptive Mesh Refinement for Hyperbolic Partial Differential Equations. J. Comp. Phy., 53, 484). It has been extended to solve → Navier-Stokes equations, time dependent problems and more. Several AMR techniques have been developed and applied to compressible flow fields to capture characteristics at the strong gradient or discontinuous regions requiring higher space resolution, such as regions involving → shock waves, vortices (→ vortex), and → wakes (see, e.g., Qingluan Xue, "Development of Adaptive Mesh Refinement Scheme and Conjugate Heat Transfer Model for Engine Simulations" (2009), Iowa State Univ., Graduate Theses and Dissertations, Paper 10678).
See also → Smoothed Particle Hydrodynamics.

→ adaptive; → mesh; → refinement.

A technique for improving the → image quality of a telescope against → atmospheric turbulence in which image distortions are compensated by high-speed changes in the shape of a small, thin mirror. → wavefront; → wavefront distortion; → wavefront correction; → Strehl ratio; → tip-tilt mirror, → Shack-Hartmann wavefront sensor, → active optics.

→ adaptive; → optics.

An → adaptive optics instrument used on the → European Southern Observatory (ESO) 3.6-m telescope at La Silla. It was an upgraded version of COME-ON-PLUS, the → Very Large Telescope (VLT) adaptive optics prototype. It had 52 → actuators and performed corrections of the mirror 200 times per second. The reference → wavefront was sensed in the → visible. The observation was done in the → near-infrared (1-5 μm).

→ adaptive; → optics; → near-infrared; → system.

An → optical system that uses → adaptive optics.

→ adaptive; → optics; → system.

1) To unite or so as to bring about an increase.
2) To increase a number by another number using addition, which leads to a → sum.

M.E. adden, from L. addere "add to, join," from → ad- "to" + -dere combining form meaning "to put, place," from dare "to give, grant," from PIE base *do- "to give" (cf. Av. and O.Pers. dâ- "to give, grant, yield," Av. dadâiti "he gives," Skt. dadâti "he gives," Gk. didomi "I give," L. do "I give").

Bardâyidan, from bar- "on; up; upon; in, into; at; forth," → on-, + O.Pers./Av. dā- "to give, grant, put," dadāiti "he gives;" Mid.Pers./Mod.Pers. dâdan "to give, put" (cf. Skt. dadáti "he gives;" Gk. tithenai "to place, put, set," didomi "I give;" L. dare "to give, offer;" Rus. delat' "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do;" PIE base *dhe- "to put, to do") + -y-, epenthetic vowel, + infinitive suffix -idan.
Afzudan, → increase.

A number or quantity to be added to another. In the expression 5 + 3, both 5 and 3 are addends.

From L. addendus "that which is to be added," → add.

Bardâyé, from present stem bardây-, → add, + noun forming suffix -é.

The operation of combining two or more quantities to obtain a third quantity called their → sum. The result of adding.

Verbal noun of → add.

The → plus sign +. It is believed to be a shortened form of the letters e and t in the L. word et, which, in early German manuscripts was the term for addition. The signs + and - were first used by Johann Wiedmann in 1489.

→ addition; → sign.

1) Involving → addition.
2) Something added to a substance to alter or improve it.

From L. additivus "added, annexed," from p.p. stem of addere, → add; → -ive.

1) Related to bardâyeš, → addition; 2) from bardây- prsent stem of bardâyidan, → add, + -é nuance suffix.

Color created by mixing light rays of different colors. Combining all the color rays of light results in white light. See also → subtractive color.

→ additive; → color.

The number which can be added to any other number without changing the magnitude of that number: zero. → multiplicative identity.

→ additive; → identity.

If E₁, E₂, ..., E_n are n → mutually exclusive events, then the probability of occurrence of at least one of them is the sum of their individual probabilities: P(E₁ + E₂ + ... + E_n) = P(E₁) + P(E₂) + ... + P(E_n).

→ additive; → law; → probability.

A binary star, in the constellation → Canis Major, 470 → light-years distant from Earth. The main star possesses an apparent magnitude of +1.5 and belongs to the spectral classification B2 II. The +7.5 magnitude companion star is 7''.5 apart from the main star.

Adhara, from Ar. adhârâ "virgins," plural of adhrâ' "virgin".

Azârâ, from Ar. Adhara.

1) To stay attached; stick fast; cling.
2) Physics: (of two or more dissimilar substances) to be united by a molecular force acting in the area of contact (→ adhesion).

From M.Fr. adhérer or directly from L. adhaerere "to stick to," from → ad- + haerere "to stick."

Âdusidan, from intensive/nuance prefix â- + dusidan (Dehxodâ) "to stick, to adhere," maybe related to Proto-Ir. *dauc- "to sew;" Pers. duxtan, duz- "to sew."

1) The act or state of adhering; adhesion.
2) The quality of adhering; steady devotion, support, or attachment (Dictionary.com).

→ adhere + -ence, → -ance.