Constellation Crux (Southern Cross)

Crux
Crux: IAU Constellation Map [150]

Properties

At 68 square degrees, Crux is the smallest, but at the same time perhaps the most famous constellation in the southern sky. It lies in a star-rich area of the Milky Way, so that the dark cloud "coal sack" stands out even more clearly against the brightly shining surroundings. If you extend the longitudinal axis of the southern cross (stars alpha and gamma crucis) just five times beyond alpha crucis, you reach the southern celestial pole, for example. The southern cross has the same task as the big chariot in the northern sky. The center of the constellation culminates around midnight on March 30th. [9, 15]

Stars with Proper Names:

  • α1 Crucis: Acrux
  • β Crucis: Becrux, Mimosa
  • γ Crucis: Gacrux
Data for constellation Crux [150]
IAU NameCrux
IAU GenitiveCrucis
IAU Abbr.Cru
English NameSouthern Cross
Season (47° N)Not visible
Right Ascension11h 56m 14s … 12h 57m 46s
Declination-64° 41' 45" … -55° 40' 38"
Area68 deg2
Neighbours (N↻)Cen, Mus

History

The constellation Crux, also Crux Australis, was formed by the sailors of the 16th century from some bright stars of the Centaurus. It served as a signpost to the south at night and was therefore an important navigational aid. The early Portuguese sailors saw this constellation as the symbol of their faith.

Like Centaurus, Crux could be observed from the Mediterranean area in antiquity, so that the stars were already known to the Greeks. Because of the precession, they have meanwhile 'drifted' south. [7]

The Southern Cross appears as a symbol in many national flags of the southern hemisphere, especially around the Australian continent.

National flag of Australia
National flag of Australia [137]

The flag of Australia was introduced in 1903 but was not recognized until 1954. In the upper left corner is the Union Jack, the coat of arms of Great Britain. Below is the Commonwealth Star or Star of Federation, which with its seven points symbolizes the seven states and united territories of the Commonwealth. In the right half is the well-known Southern Cross, which, as an important navigational aid for seafarers, made a decisive contribution to the conquest of the continent and has since been associated with Australia. The five stars shown are alpha, beta, gamma, delta crucis (all with seven points) and the weaker epsilon crucis (five point), which is missing from the national flag of New Zealand. The Australian states want to break away from Great Britain soon and they are looking for new national flags without the Union Jack on them. Most of the designs, however, still retain the Southern Cross.

National flag of Papua New Guinea
National flag of Papua New Guinea [137]

The flag of Papua New Guinea, which was introduced in 1975, has a very nice motif. It also shows the five brightest stars of the Southern Cross and also the siluette of a bird of paradise. Perhaps this siluette is supposed to represent the inconspicuous constellation Apus.

National flag of Brazil
National flag of Brazil [137]

In the blue globe of the flag of Brazil you can see that of the Southern Cross, which is roughly in the center, among many stars. These stars are supposed to represent the sky, as it appeared over Brazil on the night of November 15, 1889, when this country became a republic through a revolution. The words "Ordem e Progresso" are written on the tape on the celestial equator.

Catalogs

Yale Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991) [154]
HR B F RA [hms] Dec [dms] vMag spType dMag Sep ["]
4599θ112 03 01.5-63 18 464.33 Am 9.34.5
4603θ212 04 19.2-63 09 564.72 B2IV
4616η12 06 52.9-64 36 494.15 F2III 7.544.0
4656δ12 15 08.7-58 44 562.80 B2IV
4679ζ12 18 26.1-64 00 114.04 B2.5V 9.033.8
4700ε12 21 21.6-60 24 043.59 K3-4III
4730α112 26 35.9-63 05 571.33 B0.5IV 0.44.4
4731α212 26 36.5-63 05 581.73 B1V 0.44.4
4763γ12 31 09.9-57 06 481.63 M3.5III 5.1110.6
4764γ12 31 16.7-57 04 526.42 A3V 5.1110.6
4842ι12 45 37.9-60 58 524.69 K0III 4.827.5
4853β12 47 43.2-59 41 191.25 B0.5III 6.0371.6
4890κ12 53 49.1-60 22 375.90 B5Ia t
4897λ12 54 39.2-59 08 484.62 B4Vne
4898μ112 54 35.6-57 10 404.03 B2IV-V 1.034.9
4899μ212 54 36.8-57 10 065.17 B5Vne 1.034.9

«Revised New General Catalogue and Index Catalogue», Dr. Wolfgang Steinicke, 2021 [277]
NameRADecTypeBmagVmagDimDreyer DescriptionIdentification
NGC 4052 12 02 00.0-63 13 18OCL (II1p)8.810.00Cl, pRi, lCOCL 870, ESO 94-SC10
NGC 4103 12 06 39.5-61 15 00OCL (I3m)7.46.00Cl, pL, pC, iR, st 10…14OCL 871, ESO 130-SC5
NGC 4184 12 13 32.5-62 42 47OCL (I2p)2.00Cl, mC, st eSESO 130-SC10, OCL 877
NGC 4337 12 24 03.2-58 07 25OCL (II3p)8.93.50Cl, pRi, lC, st 12…14OCL 878, ESO 131-SC2
NGC 4349 12 24 06.0-61 52 13OCL (I2m)7.44.00Cl, vB, vL, lC, st 12…14OCL 882, ESO 131-SC3
NGC 4439 12 28 26.3-60 06 11OCL (II1p)8.44.00Cl, S, st 11…12OCL 884, ESO 131-SC6
NGC 4609 12 42 19.8-62 59 38OCL (II1p)6.96.00Cl, pL, pC, cE, st 10OCL 890, ESO 95-SC14
NGC 4755 12 53 39.0-60 21 42OCL (I3r)4.210.00Cl, vL, st vB (κ Crucis)OCL 892, ESO 131-SC16, Jewel Box, Kappa Cru cluster

References

7«Der grosse Kosmos-Himmelsführer» von Ian Ridpath und Wil Tirion; Kosmos Verlag; ISBN 3-440-05787-9
9«Drehbare Sternkarte SIRIUS» von H. Suter-Haug; Hallwag-Verlag, Bern
15«Hartung's Astronomical Objects for Southern Telescopes» by David Malin and David J. Frew; Melbourne University Press 1995; ISBN 0-522-84553-3
137Flags of the World (FOTW) Web Site; fotw.digibel.be/flags
150IAU: The Constellations, 11. Oktober 2020; iau.org/public/themes/constellations
154Yale Bright Star Catalog, 15. Oktober 2020; tdc-www.harvard.edu/catalogs/bsc5.html
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)