An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -he Haf hal har har HD hea hel hel Her Her hid hig Hip hol hor hot Hoy Hub hun hyd hyd Hyd hyp > >>

Number of Results: 478
Hipparcos (#)

Fr.: Hipparcos   

A → European Space Agency satellite, which was launched in August 1989 and operated until March 1993. It was the first space mission devoted to → astrometry with an unprecedented degree of accuracy. The telescope on Hipparcos had a main mirror of diameter 29 cm. Calculations from observations by the main instrument generated the Hipparcos Catalogue of 118,218 stars charted with the highest precision (published in 1997) containing positions, distances, → parallaxes, and → proper motions. An auxiliary star mapper pinpointed many more stars with lesser but still unprecedented accuracy, in the Tycho Catalogue of 1,058,332 stars. The Tycho 2 Catalogue, completed in 2000, brings the total to 2,539,913 stars, and includes 99% of all stars down to magnitude 11. → Gaia.

Hipparcos, acronym for → High  → Precision  → Parallax  → Collecting → Satellite, chosen for its similarity to the name of the Greek astronomer Hipparchus of Nicaea (c. 190-125 BC), one of the most influential astronomers of antiquity, who compiled an extensive star catalogue in which he gave the positions of over 1,000 stars and also classified them according to their magnitude (on a scale of 1 to 6, brightest to faintest). Ptolemy later incorporated this information into his → Almagest. In addition, he discovered the → precession of the equinoxes.


Fr.: Hippocampe   

The smallest known moon orbiting the planet → Neptune, discovered in 2013. Hippocamp has an estimated diameter of only about 34 km and orbits close to → Proteus, the outer and the second largest of Neptune's moons. The orbital → semi-major axes of the two moons differ by only 10%. Hippocamp is probably an ancient fragment of Proteus. Billions of years ago a comet collision would have chipped off a chunk of Proteus. Images from the Voyager 2 space probe from 1989 show a large → impact crater on Proteus, whose size compares with Hippocamp's (Showalter et al., 2019, Nature 566, 350).

Formerly known as S/2004 N 1, Hippocamp is named after the sea creatures in Greek and Roman mythology. The mythological Hippocampus possesses the upper body of a horse and the lower body of a fish. The Roman god Neptune would drive a sea-chariot pulled by Hippocampi.


Fr.: hippopède   

A curve described by the → polar equation  r2 = 4b (a - b sin2θ), where a and b are positive constants. For appropriate values of a and b, the curve looks like the infinity symbol, ∞. See also → spheres of Eudoxus.

Hippopede, literally "a horse's foot," denoting a "horse fetter (hobble)," from Gk. hippos, → horse, + -pede variant of -ped, combining form of pos,→ foot.

  نمودار ِ ستونی   
nemudâr-e sotuni (#)

Fr.: histogramme   

A type of graphical representation, used in statistics, in which frequency distributions are illustrated by rectangles.

Histogram, from Gk. histo-, a combining form meaning "tissue," from histos "mast, loom, beam, warp, web," literally "that which causes to stand," from histasthai "to stand," from PIE *sta- "to stand" (cf. Pers. ist-, istâdan "to stand;" O.Pers./Av. sta- "to stand, stand still; set;" Skt. sthâ- "to stand;" L. stare "to stand;" Lith. statau "place;" Goth. standan); → -gram.

Nemudâr, → diagram + sotuni "column-like," from sotun "column," from Mid.Pers. stun, from O.Pers. stênâ "column," Av. stuna-, Skt. sthuna- "column."

târixi (#)

Fr.: historique   

Of, pertaining to, treating, or characteristic of → history or past events ( → historical supernova.

history; → -al.

historical supernova
  اَبَر-نو‌اَختر ِ تاریخی   
abar-now-axtar-e târixi (#)

Fr.: supernova historique   

A supernova event recorded in the course of history before the invention of the telescope. The well recorded supernovae of this small group are SN 185, SN 1006, SN 1054 (→ Crab Nebula), SN 1181, SN 1572 (→ Tycho's star), and SN 1604 (→ Kepler's star).

historical; → supernova.

târix (#)

Fr.: histoire   

1) The branch of knowledge dealing with past events.
2) The record and explanation of past events and times, especially in connection with a particular people, country, period, person, etc. See: → star formation history, → historical supernova.

History, from M.E. histoire, historie, from O.Fr. estoire, histoire, from L. historia "narrative, tale, story," from Gk. historia "a learning or knowing by inquiry, record, account," from historein "to inquire," from histor "one who knows or sees, wise man, " from PIE *wid-tor-, from base *weid- "to know; to see;" cf. Pers. bin- "to see" (present stem of didan); Mid.Pers. wyn-; O.Pers. vain- "to see;" Av. vaēn- "to see;" Skt. veda "I know." Related to Gk. idein "to see," and to eidenai "to know," → idea.

Târix, from Ar., itself, according to Abu Rayhân Biruni (973-1048, in Athar al-Baqqiya), loan from Mid.Pers. mâhrôz "date," first Arabicized as murux, from which the infinitive taurix, and then târix.

bašm (#)

Fr.: givre, gelée   

Another name for → frost.

Hoba meteorite
  شهابسنگ ِ هوبا   
šahâbsang-e Hoba

Fr.: météorite d'Hoba   

The world's largest meteorite found in 1920, near Grootfontein, Namibia. It was discovered by Jacobus H. Brits while ploughing one of his fields with an ox. The meteorite is tabular in shape and measures 2.95 x 2.84 m; it has an average thickness of about 1 m (1.22 m maximum and 0.75 m minimum). The Hoba meteorite weighs about 65-70 tons. Its chemical composition is 82.4 % iron, 16.4 % nickel, 0.8 % Cobalt, and traces of other metals. No crater is present around the site of the meteorite, probably because it fell at a lower rate of speed than expected. The flat shape of the object may be responsible for its low velocity at impact.

Named after Hoba West, the farm it was discovered; → meteorite.

Hohmann transfer
  تراوژ ِ هوهمن   
tarâvaž-e Hohmann

Fr.: transfert de Hohmann   

An → orbital maneuver using two timed engine impulses to move a spacecraft between two coplanar circular orbits. It is performed through an elliptic orbit which is tangent to both circles at their periapses (→ periapsis).

Hohmann transfer orbit.

Hohmann transfer orbit
  مدار ِ تراوژ ِ هوهمن   
madâr-e tarâvaž-e Hohmann

Fr.: orbite de trandfer   

An elliptical orbit that is the most economical path for a spacecraft to take from one planet to another. In the case of Earth-Mars travel, the desired orbit's → perihelion will be at the distance of Earth's orbit, and the → aphelion will be at the distance of Mars' orbit. The portion of the solar orbit that takes the spacecraft from Earth to Mars is called its trajectory. Earth and Mars align properly for a Hohmann transfer once every 26 months. → Hohmann transfer.

Named after Walter Hohmann (1880-1945), German engineer, who developed basic principles and created advanced tools necessary for the conquest of space. In 1925 he published The Attainability of the Heavenly Bodies in which he described the mathematical principles that govern space vehicle motion, in particular spacecraft transfer between two orbits.

  سوراخ، چاله، چال   
surâx (#), câlé (#), câl (#)

Fr.: trou   

1) General: An opening through something; an area where something is missing; a serious discrepancy.
2) Astro.: → black hole; → coronal hole.
3) Electronics: The absence of an electron in the valency structure of a crystalline semiconductor, behaving like a positive charge carrier.

O.E. hol "orifice, hollow place," from P.Gmc. *khulaz (cf. O.H.G. hol, M.Du. hool, Ger. hohl "hollow"), from PIE base *kel- "to cover, conceal." → cell.

Surâx "hole," from Mid.Pers. sûlâk "whole, aperture," Av. sūra- "hole;" cf. Gk. koilos "hollow," L. cava "cave," cavus "hollow;" PIE base keuə- "to swell; vault, hole."
Câlé, câl "hole," from câh "a well, pit," from Mid.Pers. câh "a well;" Av. cāt- "a well," from kan- "to dig," uskən- "to dig out" (O.Pers. kan- "to dig," akaniya- "it was dug;" Mod.Pers. kandan "to dig"); cf. Skt. khan- "to dig," khanati "he digs," kha- "cavity, hollow, cave, aperture."

hole injection
  درشانش ِ سوراخ، ~ چاله   
daršâneš-e surâx, ~ câlé

Fr.: injection de trou   

The injection of holes in a semiconductor which can be produced by application of a sharp conducting point in contact with an n-type semiconductor.

hole; → injection.

  ۱) سپنت‌روز؛ ۲) آسودروز؛ ۳) آسودگان   
1) sepantruz; 2) âsudruz; 3) âsudgân

Fr.: 1); 2) férié; 3) vacances   

1) A day fixed by law or custom on which ordinary business is suspended in commemoration of some event or in honor of some person.
2) Any day of exemption from work.
3) (in plural form) A period of cessation from work or one of recreation; vacation.

O.E. haligdæg, from halig "holy," → heiligenschein, + dæg, → day.

1) Sepantruz, from sepant "holy," → heiligenschein, + ruz, → day.
2) Âsudruz, from âsud, âsudan "to rest, repose," from Mid.Pers. âsutan, Av. ā- + saē- (saii-) "to lie down, go to sleep;" + ruz, → day.
3) Âsudgân, from âsud, as before, + -gân suffix forming plurals.

haru- (#)

Fr.: holo-   

A combining form meaning "complete, entire, total, whole," used in the formation of compound words: → holonomic, → holography, holomorphic.

From M.E. holo-, from, from L. hol-, holo-, from Gk. holos "whole," akin to Pers. har- "every, all, each, any," as below.

Haru, from Mid.Pers. har(v) "all, each, every" (Mod.Pers. har "every, all, each, any"); O.Pers. haruva- "whole, all together;" Av. hauruua- "whole, at all, undamaged;" cf. Skt. sárva- "whole, all, every, undivided;" Gk. holos "whole, complete;" L. salvus "whole, safe, healthy," sollus "whole, entire, unbroken;" PIE base *sol- "whole."


Fr.: holocauste, shoa   

1) A great or complete devastation or destruction, especially by fire.
2) (usually initial capital letter, preceded by the) The systematic mass slaughter of European Jews in Nazi concentration camps during World War II (

M.E., from L.L. holocaustum, from Gk. holokaustos "burnt whole;" see → holo- "complete, entire, total," → caustic "burning; burnt."

Harusuc "entirely burnt;" → holo-, → caustic "burning; burnt."

harunegâšt (#)

Fr.: hologramme   

A three-dimensional image produced with the technique of → holography.

holo-; → -gram.


Fr.: holographique   

Of, relating to, or produced using → holography; three-dimensional.

holo- + → -graphic.

holographic grating
  توری ِ هرونگاریک   
turi-ye harunegârik

Fr.: réseau holographique   

A → diffraction grating produced from a series of constructive → interference fringes. The fringes, whose intensities vary in a sinusoidal pattern, correspond to the grooves of the grating. They are recorded on a photosensitive substrate and subsequently treated using a chemical procedure. Since the grooves are created by the interference of light, such a grating is free from the random and periodic errors present in → ruled gratings.

holographic; → grating.

harunegâri (#)

Fr.: holographie   

A technique for making three-dimensional images by recording → interference patterns from a split → laser beam on a medium such as photographic film. One of the → coherent beams irradiates the object, the second beam illuminates a recording medium. The two beams produce an interference pattern, called → hologram, on the film. The hologram contains information on both → phase and → amplitude of the object. However, this information is in a coded form, and the image must be reconstructed. When the object is removed and the hologram is illuminated by the laser from the original direction, a 3-dimensional image of the object appears where the object was originally, as if it were not removed. The visible object seems so real that the observer can detect → parallax by changing the position of one's head.

From → holo- "whole" + → -graphy. By using the term holography, Dennis Gabor (1900-1979), the Hungarian-British electrical engineer and inventor, wanted to stress that the technique records complete information about a wave, both about its amplitude and its phase, in contrast to the usual photography in which only the distribution of the amplitude is recorded.

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