Sagittarius (constellation)

Sagittarius constellation
Latin name	Sagittarius
Latin genitive	Sagittarii
Abbreviation	Sgr
Right ascension	17 h 43 m 12 s to  20 h 28 m 41 s
declination	−45 ° 16 ′ 39 ″ to  −11 ° 40 ′ 34 ″
surface	867,432 deg² rank 15
Completely visible	45 ° N to 90 ° S
Observation time for Central Europe	summer
Number of stars brighter than 3 mag	7th
Brightest star (size)	Epsilon Sagittarii (1.79)
Meteor streams
Neighboring constellations ( clockwise from north )	Eagle sign Snake (tail) Snake bearer Scorpio Southern crown telescope ( Indians ) microscope Capricorn
swell	IAU ,
The shooter with arrow and bow in the hand (similar to the view of Centaurus from the Uranographie of Johann Elert Bode )

The Sagittarius ( Latin / technical language Sagittarius , astronomical sign ♐) is a constellation of the ecliptic .

description

The constellation of Sagittarius as seen with the naked eye

Sagittarius is the southernmost zodiac constellation , it lies between Scorpio and Capricorn (Capricorn).

The brightest stars of Sagittarius form a shape reminiscent of a tea kettle. In the English-speaking world, it is therefore often referred to as "Teapot".

Sagittarius lies in the star-rich areas of the Milky Way ; in this direction is the galactic center . Therefore, in Sagittarius you can find a multitude of nebulous objects, such as open star clusters , globular star clusters and gas nebulae . Even in the prism binoculars , the shooter is a magnificent sight. However, it is not easy to observe from Germany, as it is low in the sky in summer due to its southern location.

The ecliptic runs through Sagittarius, so the sun , moon and planets move through this constellation. The sun is currently in Sagittarius from December 18 to January 20.

history

The origin of the name of the constellation probably goes back to an early people of horsemen nomads and was adopted by the Sumerians .

With the Babylonians , the stars embodied Pabilsang , a god with a lion's head and wings.

For the ancient Egyptians and Indians , the constellation represented a rider or archer.

Different interpretations existed among the ancient Greeks. So you saw another centaur in the sky or Krotos , a person who invented the art of archery.

The constellation gave its name and determined the original position of the zodiac sign Sagittarius . Due to the precession movement of the earth's axis, however, the time of the passage of the sun has shifted compared to antiquity .

Sagittarius is one of the classic 48 constellations described by Ptolemy .

In 1932 Karl Jansky discovered the powerful radio source Sagittarius A * in the Schützen . According to the current state of research, it is a supermassive black hole with approx. 4.3 million solar masses in the center of the Milky Way.

On August 15, 1977 , the so-called wow signal was presumably received by the constellation Sagittarius for 72 seconds. However, the nature of the signal remains unexplained.

mythology

Sagittarius is a difficult constellation to interpret. The centaur Cheiron is often assigned to the constellation . Not only because he was a good archer, but also because he shot an arrow at the Scorpio , which stabbed the hunter Orion and this is easily recognizable when you see the constellations Scorpio and Sagittarius side by side. This is very unlikely, however, since Cheiron can already be seen in the sky as a centaur .

The legend about the satyr Krotos , son of Pan and Eupheme , the wet nurse of the Muses , may also have been assigned later.

In addition, there is no specific indication in Greek mythology as to whether this centaur represents a special character. It could just be a normal offshoot of the centaur race. This is possible because the Greeks adopted the constellation from the Babylonians . For the Babylonians, the constellation could represent a form of their main god Marduk .

Celestial objects

Stars

B.	F.	Names or other designations	Size (mag)	Lj	Spectral class
ε	20th	Kaus Australis	1.9	143	B9.5 III
σ		Nunki	2.05	224	B2.5 V
ζ	38	Askella	2.60	89	A3 IV
δ	19th	Kaus Medius	2.72	approx. 350	K3 III
λ	22nd	Kaus Borealis	2.82	78	K0 IV
π	41	Albaldah	2.88	440	F2 II / III
γ	10	Alnasl or Nash	2.98	96	K0 III
η			3.10	149	M2 III
φ	27		3.17	231	B8.5 III
τ	40		3.31	120	K1 / K2III
ξ 2	37		3.52	372	G8 / K0II / III
ο	39	Manubrij	3.76	139	K0 III
μ	13	Polis	3.84	3912	B2 III
ρ 1	44		3.92	122	F0 III / IV
β 1		Arkab Prior	3.96	378	B9 V
α		Rukbat	3.97	170	B8 V
ι			4.12	189	K0 III
β 2		Arkab Posterior	4.27	139	F2 III
θ 1			4.37	618	B2.5 IV
		V3872	4.43	448	M4 III
υ	46		4.52	1673	F2p
	3	X	4.53	1077	F7 II
b 1	59		4.54	1208	K3 III
		HR 6766	4.55	348	K0 III Cnpvar
h 2	52		4.59	189	B8 / B9V
		HR 6842	4.66	700	K3 III
γ 1			4.66	2078	G0 Ib / II
ω	58	Omega Sagittarii	4.7	approx. 85	G5 IV
	4th		4.74	437	B9 V
		HR 7652	4.77	405	K4 III
	21st		4.81	597	A1 / A2V
	60		4.84	341	G8 II / III
ν 1	32	Ain al Rami	4.86	1853	K1 II
ψ			4.86	330	K0 / K1III
		HR 7029	4.86	451	B2 V
f	56		4.87	205	K0 III
d	43		4.88	536	K0 III
	11		4.96	244	K0III
		HR 7659	4.99	325	K1 III / IV
ν 2	35		5.00	270	K1 Ib / II
		HR 6693	5.00	935	K5 / M0III
	61		5.01	292	A2 V
χ 1	47		5.02	221	A4 IV / V
ξ 1	36		5.02	5018	B9.5 Ib
e 2	55		5.06	175	F3 IV / V
		HR 6944	5.12	213	B9 / B9.5 V
	29		5.22	750	K2 III
		HR 6960	5.28	2234	B2 III / IV
	15th		5.29		B0 / 1Ia / ab
θ 2			5.30	157	A4 / A5IV
		HR 7703	5.32	20th	K2 V
		V3961	5.32	339	A0p
		V4050	5.33	619	B7 Ib / II
	7th		5.37	1106	F2 / F3 II / III
		HR 6936	5.37	350	A5 V
	28		5.37	1279	K5 III
χ 3			5.45	506	K3 III
		HR 7454	5.46	101	F7 V
		HR 7398	5.46	254	K1 / K2 III
	14th		5.49	506	K2 III
	24		5.49	3434	K3 III
		HR 7496	5.49	120	F5 V
		HR 7211	5.49	546	A0 V

The brightest star in Sagittarius is Epsilon Sagittarii , a blue giant 145 light-years away with 250 times the luminosity of our sun. In the prism binoculars it appears as a double star . A 7th magnitude star becomes visible at a distance of 3.3 arc minutes . However, it is not a star system in which the stars are bound to one another by gravity . Both stars are only in the same direction when viewed from Earth. The name Kaus Australis is a combination of Latin and Arabic and means "southern arc".

Sigma Sagittarii , also a blue giant, is 245 light years away. The name Nunki goes back to the Sumerian god Ninki .

Zeta Sagittarii is a white shining star of spectral class A3, 89 light-years away . The name Askella means "armpit" (the archer).

The orange glowing Gamma Sagittarii is 96 light years away and belongs to the spectral class K0 III. The name Alnasl is of Arabic origin and is derived from "arrowhead".

Alpha Sagittarii is not, as is usually the case, the brightest star in the constellation, but only a third magnitude star. It is 170 light years away. His name Rukbat also comes from Arabic and denotes the "knee" of the archer .

Double stars

→ Main article : Double star

system	Vmag	distance
μ
υ

Variable stars

→ Main article : Variable star

star	size	period	Type
R.	6.7 to 12.8	268.8 days	Mira type
W.	4.3 to 5.1	7.595 days	Cepheid
X	4.3 to 4.9	7.011	Cepheid
RY	6.0 to 15		R Coronae Borealis Star
RR	6 to 14	334.6	Mira
RU	6 to 14	240.3	Mira

W and X Sagittarii are variable stars of the Cepheid type . These stars pulsate regularly and change their brightness in the process.

RR and RU Sagittarii are variables of the Mira type . Stars of this type show strong fluctuations in brightness over long periods of time.

Messier and NGC objects

→ Main articles : Messier Catalog  and New General Catalog

Messier (M)	NGC	other	Vmag	Type	Surname
M 8	6253	Lagoon fog	5.8	Gas mist	Lagoon fog
M 17	6618		7.0	Gas mist	Omega nebula, swan nebula
M 18	6613		6.9	Open star cluster
M 20	6514		8.5	Gas mist	Trifid Nebula
M 21	6531		5.9	Open star cluster
	6537		13	Planetary nebula
M 22	6656		5.1	Globular clusters
M 23	6949		5.5	Open star cluster
M 24			4.6	Cluster of stars
M 25		IC 4725	4.6	Open star cluster
M 28	6626		5.1	Globular clusters
M 54	6715		7.6	Globular clusters
M 55	6809		6.4	Globular clusters
M 69	6637		7.6	Globular clusters
M 70	6681		8.0	Globular clusters
M 75	6864		8.5	Globular clusters
	6637		7.6	Globular clusters
	6522		8.6	Open star cluster
	6544		8.3	Globular clusters
	6546		8.0	Open star cluster
	6553		8.3	Globular clusters
	6568		8.6	Open star cluster
	6595		7.0	Open star cluster
	6645		8.5	Open star cluster
	6649		8.9	Open star cluster
	6652		8.9	Open star cluster
	6716		7.5	Open star cluster
	6723		7.3	Globular clusters
	6818		10.0	Planetary nebula
	6822		8.8	Galaxy	Barnard's Galaxy

A variety of foggy objects are visible in Sagittarius. The French astronomer and comet hunter Charles Messier included fifteen in his catalog ( Messier catalog ). The Sagittarius is thus the constellation with the most "Messier objects".

However, the stars, gas and dark clouds of the Milky Way block the view of more distant objects. Therefore, only a brighter galaxy is visible in Sagittarius .

M 8 is an extensive gas nebula 6,000 light years away. An elongated dark cloud , reminiscent of a dark lagoon , protrudes into the bright emission nebula . M 8 is therefore also known as the “Lagoon Nebula”. An open star cluster is embedded in the nebula . The region around M 8 is an area of ​​active star formation. Even in smaller telescopes it is a great sight.

M 17 is an emission nebula 6,000 light years away. Even in the binoculars you can see an elongated fog. Interesting structures become visible in the telescope, especially when using an interference filter. Due to its curved shape, M 17 is also known as the Omega Nebula or Swan Nebula.

M 18 is a rather inconspicuous star cluster 4,000 light years away.

M 20 is the famous, often depicted “three-part” trifid nebula, an emission nebula 6,000 light years away. Dark bands of dust run through the fog, dividing it figuratively. However, you need good observation conditions (a dark sky without artificial lighting and haze) to see the structures.

M 21 is again a rather unspectacular open star cluster at a distance of 4,000 light years.

M 22 is a globular cluster 10,000 light years away . It is the brightest globular cluster in the northern sky and can be resolved into single stars with the telescope at the edge.

M 23 is an open star cluster 2,200 light years away. About 40 stars can be seen even with smaller telescopes.

M 24 is a dense cluster of stars in the Milky Way. With the naked eye, they appear as a "star cloud".

M 25 is an open star cluster 2,500 light years away. It can already be seen with the naked eye. About 50 stars can be seen in a smaller telescope.

M 28 is a globular cluster 20,000 light years away . In the middle telescope, the edge can be resolved into single stars.

M 54 is a globular cluster which , at 80,000 light years, is very far from the sun . Nor does it belong to the globular cluster system of our Milky Way, but to a dwarf galaxy. To resolve it into single stars you need a larger telescope.

M 55 is much closer at 18,000 light years away. The globular cluster can be completely resolved into single stars in the middle telescope.

M 69 is a globular cluster 30,000 light years away. A larger telescope is required to resolve it.

M 69 , M 70 and M 75 are globular clusters that are more difficult to observe because you need a larger telescope to resolve them. M 69 and M 70 are 30,000 light years away, M 75 60,000 light years.

NGC 6818 is a planetary nebula 6,000 light years away , i.e. the ejected gas envelope of a star. An oval greenish disc is visible in the middle telescope.

NGC 6822 is a dwarf galaxy 2 million light-years away belonging to the local group . Due to its low brightness, it is relatively difficult to observe. It was only discovered by Edward Barnard in 1884 .

See also

• List of constellations

Web links

Wiktionary: Sagittarius  - explanations of meanings, word origins, synonyms, translations

Commons : Sagittarius  - album with pictures, videos and audio files

• Sagittarius constellation

Individual evidence

1. ↑ Wissenschaft.de: A monster in its sights ( memento from July 29, 2009 in the Internet Archive ), astronomers measure the black hole in the center of the Milky Way , news from December 10, 2008
2. ↑ Werner Perrey: Constellations and their legends . Urachhaus, Stuttgart 1999, ISBN 3-8251-7172-8 .