When is the best time to observe Becrux?

Becrux is best observed from February through April, with peak visibility during March when it transits around midnight in the Northern Hemisphere.

Where is Becrux located in the sky?

Becrux lies in the constellation Crux at right ascension 12h 48m and declination -59° 41′.

What telescope do I need to see Becrux?

At magnitude 1.2, Becrux is visible to the naked eye under most conditions.

Becrux — Star in Crux

HIP 62434; Beta Crucis

Magnitude 1.2^m Star Crux (Cru) Visible

Star Map + List + Plan

About Becrux

Description

Becrux (also known as Mimosa) is the second brightest star in the constellation Crux (the Southern Cross) at magnitude 1.25. It is a blue giant of spectral type B0.5III, located about 280 light-years from Earth. Becrux is about 16 times the mass of the Sun and roughly 34,000 times more luminous. It is a Beta Cephei-type variable star, pulsating with multiple periods between 4 and 6 hours, causing small brightness fluctuations of a few hundredths of a magnitude.

Observing Tips

Becrux marks the eastern (left) arm of the Southern Cross and is visible only from latitudes south of about 20°N. The Cross is best located by using the Southern Pointers (Alpha and Beta Centauri), which point toward it. Becrux's blue-white color contrasts beautifully with the reddish Gacrux (Gamma Crucis) at the top of the Cross. The famous Jewel Box Cluster (NGC 4755) lies just 1 degree southeast of Becrux. Best observed from March through July from southern latitudes.

History

The name Mimosa may derive from the flower, though its origin is uncertain. The alternative name Becrux is a modern contraction of 'Beta Crucis.' The Southern Cross has been used for navigation by sailors in the Southern Hemisphere for centuries, and it appears on the national flags of Australia, New Zealand, Brazil, Papua New Guinea, and Samoa.

Fun Facts

Becrux's pulsation was one of the first confirmed cases of non-radial pulsation in a star — the surface oscillates in complex patterns rather than simply expanding and contracting uniformly. At its distance, if it were as close as Sirius, Becrux would be almost as bright as the full Moon.