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

The process of converting crude observational data into usable information for scientific interpretation, by correcting, rearranging, ordering, and simplifying.

→ data; → reduction.

A → method or → format for organizing and storing data. Any data structure is designed to organize data to suit a specific purpose so that it can be accessed and worked with in appropriate ways. In computer programming, a data structure may be selected or designed to store data for the purpose of working on it with various algorithms.

→ data; → structure.

To correct the intensity or flux of a spectral line by eliminating the → reddening effect of → interstellar dust.

De-redden, from → de- + redden verb of → red.

Vâsorxidan, from vâ-, → de-, + sorxidan verb of sorx, → red.

A magnitude which has been corrected for the interstellar reddening.

De-reddened, p.p. of → de-redden; → magnitude.

Borz, → magnitude; vâsorxidé p.p. of vâsorxidan, → de-redden.

The process that de-reddens. The state of being de-reddened.

Verbal noun of → de-redden.

The characteristic → temperature of the → crystal as given by the → Debye model of → specific heats.

→ debye; → temperature.

A representation of a real number between 0 and 1, as written a = d₁d₂d₃ ..., where each d_i is one of the digits 0, 1, 2, ..., 9. This means that a = d₁ x 10^-1 + d₂ x 10^-2 + d₃ x 10^-3+ ...

→ decimal; → representation.

1) To make known or state clearly, especially in explicit or formal terms.
2) To announce officially; proclaim (Dictionary.com).

M.E. declaren, from O.Fr. declarer "explain, elucidate," from L. declarare "make clear, reveal, disclose, announce," from → de- intensive prefix + clarare "clarify," from clarus, → clear.

From Kurd. (Sorani) rûnâk, runâg "clear, bright," rûn "bright, clear," rûn kirdin "to explain," variants of rowšanâ, rowšan, rušanâ, → bright, → day.

To cause to undergo → decompression.

→ de- + → compress.

1) A gradual decrease in surrounding → pressure, especially the controlled decrease in pressure that divers undergo after working in deep water or breathing compressed air.
2) Computers: The restoration of compressed electronic data to their full size.

→ de- + → compression.

1) (v.tr.) To cause to diminish, to make less. (v.intr.) To diminish or lessen in extent, quantity, power, etc.
2) The act or process of decreasing; condition of being decreased. → Forbush decrease.

Decrease, from M.E. decres (n.), decresen, from O.Fr. descreistre, from L. decrescere, from → de- + crescere "to grow," → crescent.

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.
2) Math.: The quantity by which a variable is decreased. A negative → increment.
3) Physics: 1) The ratio of the amplitude of an oscillation to that of its succeeding oscillation in an underdamped vibrating system. 2) The intensity ratio of a series of spectral lines of the same nature, such as → Balmer decrement.

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.

From → de- "reversal, removal," + -cretion, from L. accretionem (nom. accretio, gen. accretionis) "a growing larger," from stem of accrescere, → accretion.

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.

→ decretion; → disk.

Reasoning from the → general to the → particular (or from → cause to → effect).

→ deductive; → reasoning.

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.

→ deep; → exposure.

In Ptolemy's geocentric model, the circle around the Earth in which the center of the → epicycle of a body was thought to move.

Deferent, from L. deferent-, pr.p. of deferre "to carry from or down, transfer" from → de- + ferre "to carry, bear," from PIE *bher- "to bear, to carry, to take" (cf. O.Pers./Av. bar- "to bear, carry," barəθre "to bear" (infinitive), Mod.Pers. bordan, bar- "to carry," Skt. bharati "he carries," Gk. pherein "to carry").

Falak-e hâmel, from Ar. falak "heaven; orbit, sphere" + hamil "carrier."

In a CCD detector, phenomenon caused by charge traps or potential pockets, which prevent electrons from being released to the adjacent pixel; eventually the electrons may be released in a subsequent cycle.

Differed, p.p. of differ, from O.Fr. différer, from L. differre "set apart, put off, delay," also "be different, differ," → differ; → charge.

Bâr→ charge; bâzdâšté "prevented," p.p. of bâzdâštan, from preventive suffix bâz- + dâštan "to hold, have, maintain," Mid.Pers. dâštan, O.Pers./Av. root dar- "to hold, keep back, maitain, keep in mind," Skt. dhar- "to hold, keep, preserve," dharma- "law," Gk. thronos "elevated seat, throne," L. firmus "firm, stable," Lith. daryti "to make," PIE *dher- "to hold, support."

Pressure in a degenerate electron or neutron gas. → degenerate matter.

→ degeneracy; → pressure.

1) Subdivision of an interval in a scale of measurement.
2) Geometry: Measure of angle, the 360th part of a circle.
3) Math.: Rank of an equation or expression as determined by the sum of the exponents of the variables.

From O.Fr. degré, from V.L. *degradus "a step," from L.L. degredare, from L. → de- "down" + gradus "step."

Darajé, from Ar. darajat "step, ladder."