COSMOS / CONSTELLATIONS / CRU
Crux (Southern Cross)
The Southern Cross. IAU abbreviation Cru.
STAR CHART
KEY FACTS
- IAU abbreviation
- Cru
- Latin name / genitive
- Crux / Crucis
- Position
- Right ascension ≈ 12 h 27 m; declination −65° to −56°
- Visibility from Türkiye
- Not visible from Türkiye; it is observed from the southern hemisphere.
- Best time to observe
- From the southern hemisphere it is best placed around 21:00 in early May.
- Number of stars
- 47 stars brighter than magnitude 6.5 in the catalogue; 14 brighter than 5 and 5 brighter than 4.
INTERACTIVE LAB
Where is Crux tonight?
This constellation cannot be seen from Türkiye, so the lab opens for Sydney. Drag the time slider through the southern night, use the “Best night” button to jump to the best date, and switch the city to Ankara to see why it never rises there.
MYTH, HISTORY AND OBSERVING
The smallest of the 88 constellations; in antiquity it was part of Centaurus and was first shown separately in the late 16th century. Because of precession it was visible from the Mediterranean about two thousand years ago; today it never rises from Türkiye. The Coalsack dark nebula and the Jewel Box cluster (NGC 4755) are here.
BRIGHTEST STARS
| Star | Magnitude | Distance (light-years) | Spectral type |
|---|---|---|---|
| Acrux | 0.77 | 322 | B0.5IV |
| Mimosa | 1.25 | 279 | B0.5III |
| Gacrux | 1.59 | 89 | M4III |
| Imai | 2.79 | 345 | B2IV |
| Ginan | 3.59 | 230 | K3/K4III |
| μ¹ Cru | 4.03 | 414 | B2IV-V |
| ζ Cru | 4.06 | 358 | B2.5V |
| η Cru | 4.14 | 64 | F2III |
Magnitude: apparent brightness; the smaller the number, the brighter the star. Distances derive from parallax measurements and are uncertain for distant stars. Source: HYG v4.1 star catalogue (CC BY-SA 4.0).
SOURCES
Position, visibility and best observing time were computed approximately for this page from the catalogue stars (Ankara, 39.9° N). The 88 constellations were adopted by the IAU in 1922; their boundaries were drawn by Eugène Delporte in 1930.