crux
Mountaineering the most difficult and often decisive part of a climb or pitch
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
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Crus and nearby bright constellations
Crux
(kruks) (Crux Australis; Southern Cross) The smallest but one of the most conspicuous of all the constellations in the sky, located in the southern hemisphere and lying in the Milky Way. The four brightest stars, Alpha (α), Beta (β), Gamma (γ), and Delta (δ) Crucis form a cross (see illustration). The zero-magnitude Alpha and the 1st-magnitude red giant Gamma form the longer arm that points approximately to the south celestial pole. The 1st-magnitude Beta and 2nd-magnitude Delta form the transverse arm. The 3rd-magnitude Epsilon (Ɛ), between Alpha and Delta, interferes with the figure's regularity. The area also contains the brilliant cluster the Jewel Box and the dark Coalsack nebula. Abbrev.: Cru; genitive form: Crucis; approx. position: RA 12.5h, dec –60°; area: 68 sq deg.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
Crux
[kru̇ks] (astronomy)
A constellation having four principal bright stars which form the figure of a cross; right ascension 12 hours, declination 60°S. Abbreviated Cru. Also known as Cross; Southern Cross.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.