α. 1800s– antiapex.
β. 1800s– antapex.
antapexn.
/antˈeɪpɛks/, U.S. /æntˈeɪˌpɛks/ Astronomy.
The point on the celestial sphere, situated in the southern constellation Columba, away from which the solar system is moving relative to nearby stars; the point diametrically opposite to the solar apex (apex n.1 6); more fully solar antapex. Also: the point on the celestial sphere away from which the earth is moving at any given moment in its orbital motion round the sun.As a result of the motion of the solar system, stars appear to be converging on the antapex and diverging from the apex.
ΘΚΠ
the world > the universe > sun > position > [noun] > apex > point opposite
antapex1869
1869 Rep. 38th Meeting Brit. Assoc. Advancem. Sci. 1868 409 The apex was seldom seen above, and the anti-apex was rarely hidden below the horizon during the observations.
1890 A. M. Clerke Syst. Stars xxiii. 320 There would be the semblance of a general retreat from the ‘apex’ or solar point de mire, coupled with a thronging-in from all sides towards the opposite point, or ‘anti-apex’.
1926 C. W. L. Charlier Motion & Distribution Stars ii. 15 In other parts of the sky the relative motion of the stars must..be smaller than in the direction of the Apex and Antiapex.
1969 Jrnl. Brit. Astron. Assoc. 79 487 The object is a classic case of a meteoroid overtaking the Earth from behind, from the direction only 10° to one side of the antapex point.
1992 D. A. Rothery Satellites Outer Planets v. 73 Craters more than 60 km in diameter are twice as abundant near its apex of orbital motion (i.e. in the middle of its leading hemisphere) than near the antapex of motion.
1994 J. North Fontana Hist. Astron. & Cosmol. xiv. 397 Those in the direction away from which we move (the ‘solar antapex’) will seem to close up on one another, and to draw towards the antapex.
This entry has been updated (OED Third Edition, March 2016; most recently modified version published online December 2021).
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