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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 3106 Search : on
comet designation
  نامگزینی ِ دنباله‌دار   
nâmgozini-ye donbâledâr

Fr.: désignation des comètes   

A → nomenclature system for naming → comets. In early 1995, a new comet designation system was established by the → International Astronomical Union. The main rules are as follows:
a) If the comet is a newly discovered one, it first gets a provisional name, which closely matches the → asteroid designation system. For example, the first comet discovered in the first half of 1998 January is designated 1998 A1, the second 1998 A2, etc.
b) The name of the person(s) who discovered the comet may be added to this designation (limited, however, to three names). For example, comet → Hale-Bopp (C/1995 O1) has its full name as Hale-Bopp C/1995 O1, whereas its designation is C/1998 O1. If several people are involved with a discovery at an observatory, the comet may be named after the observatory instead of the individuals.
c) → Long-period comets and one-apparition → periodic comets receive only a provisional designation.
d) A → short-period comet would get the P/designation until it is recovered in a second → apparition. At this point, the P/Year designation would be replaced with a number followed immediately by an upper case P, and a slash followed by the name of the discoverer(s). The number here is one more than the number of known periodic comets that have reappeared. For example, the comet Hug-Bell (P/1999 X1) was given the full name 178P/Hug-Bell after it reappeared in 2007. Previously, 177 periodic comets had got assigned numbers.
e) Long-period comets are indicated by the prefix C.
f) If the comet is destroyed, or if it fails to appear after several apparitions, it would be prefixed D/ (→ defunct comet) followed by the year of its discovery. For example, → Comet Shoemaker-Levy 9 has been assigned D/1993 F2 since it was discovered in the second half of March in 1993 and was destroyed when it crashed into Jupiter in 1994.
g) Comets that lack sufficient position measurements for an orbital determination are given the designation of X/ followed by the year of their discovery and the appropriate letter and number code.
h) When a → comet nucleus nucleus splits, each fragment is given the comet designation followed by A, B, C, etc (for fragments).

comet; → designation.

commissioning
  راه اندازش   
râhandâzeš

Fr.: rodage   

Putting a telescope or an observing instrument into active service after their final construction.

From L. commissionem "delegation of business," from commissus, p.p. of committere "to bring together," from → com- "together" + mittere "to put, send."

Râhandâzeš, verbal noun from compound verb râhandâxtan "to set in work; to prepare," from râh "way, path" + andâxtan "to cast; to make, do; to throw."

commissioning period
  دوره‌ی ِ راه اندازش   
dowre-ye râhandâzeš

Fr.: période de rodage   

A period during which a newly constructed observing instrument is used for test.

commissioning; → period.

common
  همدار   
hamdâr

Fr.: commun   

Belonging to or shared by two or more or all in question. → common denominator, → least common multiplier.

From M.E. comun, from O.Fr. comun, from L. communis "in common, public, general, shared by all or many," originally "sharing common duties," akin to munia "duties, public duties, functions," from munus "task, duty, gift."

Hamdâr, literally "possessing together, sharing together," from ham-, → com-, + dâr present stem of dâštan "to have, to possess," from Mid.Pers. dâštan, O.Pers./Av. root dar- "to hold, keep back, maitain, keep in mind," Skt. dhr-, dharma- "law," Gk. thronos "elevated seat, throne," L. firmus "firm, stable," Lith. daryti "to make," PIE *dher- "to hold, support."

common denominator
  آنامنگر ِ همدار   
ânâmengar-e hamdâr

Fr.: dénominateur commun   

A quantity into which all the denominators of a set of fractions may be divided without a remainder.

common; → denominator.

common fraction
  برخه‌ی ِ همدار   
barxe-ye hamdâr

Fr.: fraction d'entiers   

A fraction written as a/b where a and b are → positive  → integers, as opposed to a → decimal fraction; for example, 5/7. Common fractions are sometimes also called → vulgar fractions.

common; → fraction.

common logarithm
  لگاریتم ِ دهدهی   
logâritm-e dahdahi

Fr.: logarithme décimal   

The logarithm with → base 10. It is known also as the → decimal logarithm, decadic logarithm, or Briggsian logarithm, after Henry Briggs, an English mathematician who pioneered its use.

common; → logarithm; → decimal.

common year
  سال ِ همدار   
sâl-e hamdâr

Fr.: année commune   

A calendar year which is not a → leap year. In the → Gregorian calendar, a year with 365 days divided into 12 → months, and only 28 days in February. In the → Iranian calendar, a year consisting of 365 days with 12 months, and only 29 days in the month of Esfand.

common; → year.

commonalty
  پاترم   
pâtram (#)

Fr.: peuple, foule   

The ordinary people, as distinguished from those with authority, rank, station, etc.; the common people. Also, commonality (Dictionary.com).

M.E., from M.Fr. comunalte, from comunal- "communal," → common, + -te "-ty," a suffix denoting state, quality, etc.

Mid.Pers. pâtram "common people, commonalty" (MacKenzie), variant pâyram, prefixed from ram "herd, flock," Mod.Pers. ramé "herd, flock."

commonness
  همداری   
hamdâri

Fr.: caractère commun, banalité   

The fact or state of being → common or happening often.

common; → -ness.

communication
  همدارگنش   
hamdârganeš

Fr.: communication   

1) The act or process of communicating; fact of being communicated.
2) The imparting or interchange of thoughts, opinions, or information by speech, writing, or signs (Dictionary.com).

Verbal noun of → communicate.

commutation
  آموتش   
âmuteš

Fr.: commutation   

General: A substitution, exchange, or interchange.
Electronics: The transfer of current from one channel to another in a gas tube.
Electricity: The reversal of direct current into alternating current.
Math: A commutative operation, where a . b = b . a.

Noun from → commute.

commutation rules
  رزن‌های ِ آموتش   
razanhâ-ye âmuteš

Fr.: règles de commutation   

The specification of commutators of operators that in quantum physics correspond to the coordinates and momenta of a system.

commutation; → rule.

compact H II region
  ناحیه‌ی ِ H IIی ِ همپک   
nâhiye-ye H II-ye hampak

Fr.: région H II compacte   

A Galactic H II region with an electron density ≥ 103 cm-3 and of a linear dimension ≤ 1 pc.

compact; → H II region.

compactification
  همپکانش   
hampakâneš

Fr.: compactification   

1) Math.: A process applied to topological spaces having many dimensions to make them compact spaces.
2) Physics: In string theory, the process of "curling up" the extra dimensions (six in the superstring theory). According to these theories, the Universe actually has 10 spatial dimensions but that 7 of them have become "compactified" down to subatomic size and thus are unobservable.

Compactification, n. from → compactify.

compaction
  همپکش   
hampakeš

Fr.: compactage   

1) The act of compacting or the state of being compacted.
2) Geology: The physical process whereby the volume of a fixed mass of sediment reduces either by the weight of overlying deposits or by the pressure of earth movements.

compact; → -tion.

companion
  همدم   
hamdam (#)

Fr.: compagnon   

The fainter of the two components in a → binary system.

Companion from O.Fr. compaignon "fellow, mate," from L.L. companionem, lit. "bread fellow, messmate," from L. → com- "with" + panis "bread."

Hamdam "bearthing together, i.e. an intimate companion, friend," from ham- "with", → com- + dam "breath," Mod.Pers./Mid.Pers. damidan "to breathe, blow," Av. dāδmainya- "blowing up," cp. Skt. dham- "to blow," dhamati "he bows," Proto-Indo-Iranian *dhamH-, Proto-Iranian *damH- "to blow, breathe; to swell," PIE *dhemH- "to blow."

companion of Sirius
  همدم ِ تیشتر   
hamdam-e Tištar

Fr.: compagnon de Sirius   

A faint star of 8th magnitude in a binary system with → Sirius. Called also Sirius B, it is a → white dwarf with a mass comparable to that of the Sun, but with a diameter smaller than that of the Earth. The mean distance between the stars is about 20 A.U. (angular separation 4.6 seconds of arc), and their period of revolution about 50 years. This star was discovered in 1844 by Friedrich Bessel, who noticed that Sirius had a slight wobbling motion, as if it was orbiting an unseen object. In 1863, the optician and telescope maker Alvan Clark spotted the companion. The star was later determined to be a → white dwarf.

companion; → Sirius.

comparison
  هم‌سنجش   
hamsanješ (#)

Fr.: comparaison   

The act of comparing or the process of being compared.

From O.Fr. comparaison from L. comparationem, from p.p. stem of comparare, → compare.

Hamsanješ, from hamsanj present tense stem of hamsanjidan, → compare, + verbal noun suffix.

comparison spectrum
  بیناب ِ هم‌سنجش   
binâb-e hamsanješ

Fr.: spectre de comparaison   

A spectrum of known substances used as a standard of comparison for investigating spectra of celestial objects.

comparison; → spectrum.

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