An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 6 Search : tilt
axial tilt
  گرای ِ آسه   
gerâ-ye âsé

Fr.: inclinaison de l'axe   

The angle between an object's → rotation axis and its → orbital axis. In other words, the angle between its → equatorial plane and → orbital plane. Same as → axial inclination and → obliquity, but not to be confounded with → orbital inclination.

axial; → tilt.

solar axial tilt
  گرای ِ آسه‌ی ِ خورشید   
gerâ-ye âse-ye xoršid

Fr.: inclinaison de l'axe du Soleil   

The angle between the Sun's → rotation axis and perpendicular to the → ecliptic plane. In other words, the inclination of the Sun's → equator with respect to the → ecliptic plane. It is 7.25 degrees.

solar; → axial; → tilt.

tilt
  گرا   
gerâ

Fr.: inclinaison   

Optics: A deviation in the propagation direction of a beam of light. Tilt quantizes the average slope in both the X and Y directions of a → wavefront or phase profile across the pupil of an optical system.

M.E. tylten "to upset, tumble," from tealt "unsteady" (cf. O.N. tyllast "to trip," Swed. tulta "to waddle," Norw. tylta "to walk on tip-toe," M.Du. touteren "to swing").

Gerâ, present stem of gerâyidan "to incline toward; to intend; to make for." Gerâ may be a variant of Mod.Pers. kil "bent, inclined" (k/g and l/r interchanges), from PIE base *klei- "to lean, incline," cognate with L. clinare "to bend" (E. declination, inclination, etc.), Gk. klinein "to cause to slope, slant, incline," Skt. sri- "to lean," O.Pers. θray-, Av. sray- "to lean," P.Gmc. *khlinen (Ger. lehnen, E. lean).

tilt angle
  زاویه‌ی ِ گرا   
zâviye-ye gerâ

Fr.: angle d'inclinaison   

The angle a rocket makes with the vertical as it curves along its trajectory.

tilt; → angle.

tip-tilt mirror
  آینه‌یِ کج-و-راست-گر   
âyene-ye kaj-o-râst-gar

Fr.: miroir inclinable   

A rapidly moving → mirror used in → adaptive optics to correct overall movements of the incoming → wavefront of light caused by → atmospheric turbulence. The simplest form of adaptive optics is tip-tilt correction, which corresponds to correction of the tilts of the wavefront in two dimensions. This is done by tipping and tilting the mirror rapidly in response to overall changes in position of a reference star. See also → deformable mirror.

From, tip noun from tip (v.) "to overturn, upset," from M.E. typen "to upset, overturn" + tilt noun from tilt (v.) "to cause to lean, incline, slope, or slant," → tilt; → mirror.

Âyené, → mirror; kaj "turned aside; crooked, bent" (cf. Skt. kubja- "hump-backed, crooked," Pali kujja- "bent," L. gibbus "hump, hunch," Lith. kupra "hump") + -o- "and" + râstright + -gar agent noun suffix → -or.

wavefront tilt
  گرای ِ پیشان ِ موج   
gerâ-ye pišân-e mowj

Fr.: inclinaison du front d'onde   

The average slope in both the X and Y directions of a → wavefront or phase profile across the pupil of an optical system.

wavefront; → tilt.