Alpha Crucis - Etymology

Etymology

"Acrux" is an "Americanism" for the full Bayer designation "Alpha Crucis", coined in the 19th century, but entering common use only by the mid 20th century.

Since Acrux is at −63° declination, the southermost first-magnitude star, it is only visible south of latitude 27°N. Therefore, it barely rises from cities such as Miami, Florida, or Karachi, Pakistan (both around 25°N) and not at all from New Orleans, Louisiana, or Cairo, Egypt (both about 30°N). Because of Earth's axial precession, however, the star was visible to ancient Hindu astronomers in India who named it “Tri-shanku”. It was also visible to the ancient Romans and Greeks, who regarded it to be part of the constellation Centaurus.

In Chinese, 十字架 (Shí Zì Jià), meaning Cross, refers to an asterism consisting of α Crucis, γ Crucis, β Crucis and δ Crucis. Consequently, α Crucis itself is known as 十字架二 (Shí Zì Jià èr, English: the Second Star of Cross.).

This star is become Estrela de Magalhães (Star of Magalhães) in Portuguese.

Acrux is represented in the flags of Australia, New Zealand and Papua New Guinea as one of five stars which comprise the Southern Cross. It is also featured in the flag of Brazil, along with 26 other stars, each of which represents a state. Acrux represents the State of São Paulo.