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

A map projection on which the → azimuths of all points are shown correctly with respect to the center. A plane tangent to one of the Earth's poles is the basis for polar azimuthal projection.

→ azimuthal; → projection.

A method for estimating the real orientation of a field and/or related velocities/separations from two-dimensional images.

→ de-; → projection.

The projection of a spherical surface onto a plane through a point. A gnomonic → map projection displays all great circles as straight lines, and therefore indicates the shortest path between two points. Small circles are projected as conic sections.

→ gnomon; → -ic; → projection.

The theory and method of transforming the features, geometry, and topology on a sphere surface (in particular the spherical Earth) onto a plane.

→ map; → projection.

1) (n.) A specific task or planned program of investigation, especially in scholarship.
2a) (v.) To propose, contemplate, or plan.
2b) To throw or cause to fall upon a surface or into space, as a ray of light or a shadow.
2c) To cause (a figure or image) to appear, as on a background.
2d) Geometry: To transform the points of one figure into those of another by a correspondence between points.

1) From L. projectum "something thrown forth," noun use of neuter of projectus, p.p. of projicere "to stretch out, throw forth," from → pro- "forward" + combining form of jacere (p.p. jactus) "to throw."
2) From L. projectus, as above.

Farâšândan, from farâ- "forward," → pro- + šândan, from ešândan "to eject," from Hamadâni ešândan "to throw out," Laki owštan "to throw, to shoot (with bow and arrow);" Lori šane "throwing," šane kerde "to throw;" Av. ah- "to throw," present ahya- "throws," asta- "thrown, shot," astar- "thrower, shooter;" cf. Khotanese ah- "to throw, shoot," Skt. as- "to throw, shoot," ásyati "throws," ásana- "throw, shot," asanā- "missile."

A person who directs a project.

→ project; → director.

A person who is responsible for directing and controlling the work and staff of a project.

→ project; → manager.

The → angular velocity of a star deduced from the → rotational broadening of its → spectral lines. It is expressed as v sini, where i is the → inclination of the rotational axis with respect to the normal to the → plane of the sky. The real equatorial rotational velocity can be determined only if the inclination of the rotational axis is known.

Projected, p.p. of → project; → rotational; → velocity.

A body projected or impelled forward, as through the air.

From Mod.L. projectilis, from L. projectus, p.p. of proicere; → project.

Partâbé, from partâb "a throw, an arrow that flies far," partâbidan "to throw," from Proto-Iranian *para-tau-, from *para- "forward," → pro- + *tau- "to throw, spread, sow;" cf. Tabari tâb "throwing," tâb dəən "to throw;" Chorasmian mftw- "to perish, be destroyed, disturbed;" Ossetic aeftawyn "to throw on; to increase; to pull out."

1) The act, process, or result of projecting.
2) The act of reproducing on a surface, by optical means, a remote image on a film, slide, etc.

Verbal noun of → project.

An apparatus for projecting an image from a film, a slide onto a screen.
A device for projecting a beam of light.

→ project + → -or.

A graphical method of depicting three-dimensional geometrical objects in two dimensions. In a → planispheric astrolabe, it is the projection of a point of the celestial sphere onto the equatorial plane, as seen from one of the poles. The center of projection is the South pole for the northern hemisphere, and the North pole for the southern hemisphere. In this operation the projection of any circle of the sphere remains a circle on the projection plane and moreover the projection does not alter angles.

→ stereographic; → projection