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

A six-branch modification of the → Maxwell bridge that measures → inductance in terms of → resistance and → capacitance.

A. Anderson (1891, Phil. Mag. (5) 31, 329); → bridge.

Being neither distinguishably → masculine nor → feminine, as in dress, appearance, or behavior (TheFreeDictionary.com).

From L. androgynus, from Gk. androgynos "male and female in one; womanish man; hermaphrodite," from andros, genitive of aner "male," from PIE root *ner-, Pers. nar, → male, + gyne "woman," from PIE root *gwen- "woman," Pers. zan, → woman.

Merâcen, literally "man-woman," from merâ, from Ardestâni, Nâini, Tarqi (Natanz) mera "man," cf. Tâti malle "man," Pers. mir "master," Mid.Pers. mêrak "(young) man" + Gorgâni cen "woman," variant Pers. zan, → woman.

The state of appearing to be neither feminine nor masculine.

Noun from → androgynous.

A northern constellation between → Perseus and → Pegasus located at approximately R.A. 1h, Dec. +40 deg. Abbreviation And, Genitive form Andromedae.

In Gk. mythology, Andromeda was the princess of Ethiopia, daughter of → Cepheus and → Cassiopeia. The queen Cassiopeia angered Poseidon by saying that Andromeda (or possibly Cassiopeia herself) was more beautiful than the Nereids. Poseidon sent a sea monster to prey upon the country; he could be appeased only by the sacrifice of the king's daughter. Andromeda in sacrifice was chained to a rock by the sea; but she was rescued by → Perseus, who killed the monster and later married her. Cassiopeia, Cepheus, and Andromeda were all set among the stars as constellations.

Zan-e bé Zanjir Basté "the chained woman," coined by the 11th century astronomer Biruni, from Ar. Emra'at al-mosalsalah "the chained woman," from the Gk. mythology.

The nearest → spiral galaxy to our own and a major member of the → Local Group. It lies in the constellation → Andromeda and is the most remote object normally visible to the naked eye. The earliest known reference to this galaxy is by the Iranian astronomer Sufi who called it "the little cloud" in his Book of Fixed Stars (A.D. 964).

→ Andromeda; → galaxy.

A meteor shower which appears about 25 November with its → radiant located in the constellation → Andromeda. The Andromedids are the debris of → Biela's comet. The short-period comet, discovered in 1826, split into two parts in the middle of the 19th century and later vanished. Hence their alternative name Bielids.

Andromedids, from Andromeda constellation + → -ids suffix denoting "descendant of, belonging to the family of."

Ândromedâiyân, from Ândromedâ + -iyân, → -ids.

An instrument for measuring and indicating the force or speed of the wind.

From Gk. anemos "wind" + → -meter.

Bâdsanj, from bâd "wind" + -sanj, → -meter.

The figure formed by two lines extending from a common point; the figure formed by two intersecting planes (dihedral angle).

L. angulum (nominative angulus) "corner," a dim. form from PIE *ang-/*ank- "to bend;" cf. Skt. ankah "hook, bent," Gk. angkon "elbow," angkura "anchor," Lith. anka "loop," O.E. ancleo "ankle," O.H.G. ango "hook," Av. ank- "curved, crooked," Av. angušta- "toe," Mod.Pers. angošt, angol, angul "finger".

Zâviyé from Ar. zâwiyat "corner, angle".
Gušé "corner, angle," Mid.Pers. gošak "corner."
Konj, "angle, corner," → diagonal.

The angle between the → incident ray of light entering an → optical system (such as a prism) and the → refracted ray that emerges from the system. Because of the different indices of refraction for the different wavelengths of visible light, the angle of deviation varies with wavelength.

→ angle; → deviation.

The angle of the light coming out of a medium. For a medium with parallel sides (such as a glass slab) it is equal to the angle of incidence.

→ angle; → emergence.

The angle formed between a ray of light striking a surface and the normal to that surface at the point of incidence. Also called → incidence angle.

→ angle; → incidence.

1) General: The angle between one plane and another, or the angle formed by a reference axis and a given line.
2) Binary systems: The angle between the plane of the orbit and the → plane of the sky.
3) Rotating stars: The angle between the → equatorial plane and the → plane of the sky.

→ angle; → inclination.

The angle between the light entering and exiting the prism when the light passing through the prism is parallel to the prism's base. Angle of minimum deviation (D) is used to measure the → index of refraction (n) of the prism glass, because: n = sin [(A + D)/2]/sin (A/2), where A is the → prism angle.

→ angle; → minimum; → deviation.

→ prism angle.

→ angle; → prism.

The angle between the reflected ray and the normal to the reflecting surface.

→ angle; → reflection.

The angle between the direction in which a ray is refracted and the normal to the refracting surface.

→ angle; → refraction.

Unit of length used to describe wavelengths and interatomic distances. 1 Å = 10^-10 m.

Named after Anders Jonas Ångström, Swedish physicist and astronomer who founded the science of spectroscopy and discovered by studying the solar spectrum that there is hydrogen in the Sun's atmosphere; → unit.

Having, forming, or consisting of an → angle or angles.

From L. angularis "having corners or angles," from angulus→ angle.

Zâviye-yi, adj. from zâviyé, → angle.

The rate of change of → angular velocity. It is equal to the → first derivative of the → angular velocity: α = dω/dt =d²θ/dt² = a_t/r, where θ is the angle rotated, a_t is the linear tangential acceleration, and r is the radius of circular path.

→ angular; → acceleration.

The apparent diameter of an object in angular measure.

→ angular; → diameter.