Cygnus

Authors: Youla Azkarrula, Susanne M Hoffmann, Doris Vickers

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Cyg star chart (IAU and Sky & Telescope magazine, Roger Sinnott & Rick Fienberg).

Cygnus, the Swan, one of the 88 IAU constellations. In the original Greek, the constellation is called ‘bird’, and only the star legend tells us what kind of bird it is supposed to be. The figure is Greek.

Today, we depict it as a swan, viewed from directly above, which is why it has the simplified shape of a cross: it is therefore also called the ‘Cross of the North’. In ancient times, however, the depiction was asymmetrical. One can see one of the bird's feet resting on the Arctic Circle. The neck is not perfectly straight, and while one wing is stretched out, the other appears to be folded, which is probably meant to be a perspective effect.

Etymology and History

Cyg, Lyr, Del, Aql and Sge on the Kugel Globe (1st century BCE), SMH 2024.

Origin of Constellation

The Greek constellation was originally named "The Bird" (ornithos). In Babylonian uranography, there is a figure of a giant storm demon named U₄.KA.DU₈.A, literally meaning ‘the one with the open mouth’. It is not known exactly what this demon may have looked like, but there is an image on reliefs at a temple entrance in Nimrud that could fit: it is a panther-headed demon with wings and fearsome claws, standing between the weather god and the god of war, turning towards the weather god with its mouth wide open. This demon could be described as a panther griffin. This fits with the later Akkadian vocabulary for this constellation, as the Sumerian word U₄.KA.DU₈.A can also be written in Akkadian as nimru (panther).

Such a figure can also be seen very clearly in the stars of Cygnus and Cepheus. However, the Babylonian constellation covers a much larger area, i.e. approximately two Greek constellations. It extends to the star λ Andromedae as the foot of the demon and covers parts of Cepheus in addition to Cygnus. Therefore, it must have undergone numerous transformations to be considered one of the precursors. It cannot have been adopted directly from Babylonian into Greek.

Babylonian

see

• UD.KA.DU₈.A (𒌓𒅗𒂃𒀀)

Greco-Roman

Aratus

[275] Yes, there is even a dappled Bird accompanying Zeus, hazy in some parts, while other parts on it bristle with stars, not very bright, though still not dim. Just like a bird in fair-weather flight, it glides on the breeze towards the horizon, stretching its right wing-tip in the direction of Cepheus’ right hand, [281] while close to its left wing lies the prancing Horse. (Kidd 1997)

Hipparchus

Rising (Lib II Cap V §7)

The Rising of ...

	east		south
	lam1	lam2	lam1	lam2
	Lib 26.5	Srg 22	Leo 1.0	Lib 9.5
star
duration	4 2/5 hours = 264 min = 66 degree

Setting (Lib II Cap VI §7)

	west		south
	lam1	lam2	lam1	lam2
	Aqr 4 1/2	Psc 14	Ari 23 1/2	Gem 12
star	the one at the beak	the northern one of those at the end of the right wing
duration	3 1/6 hours = 190 min = 47 1/2°

Stars Mentioned

	Greek	German	English	ident.	src		lam_culm
					Lib II Cap V §10	rising, east, first
					Lib II Cap V §10	rising, east, last
					Lib II Cap VI §2	setting CrB, south, last	Psc 13.5
					Lib II Cap VI §13	setting Aql, south, first	Ari 2
					Lib III Cap I §9	rising Ori, south, last	Psc 13

Hyginus, Astronomica

The sign the Greeks call the Swan, but others, out of ignorance of the story, have called it ornis, the general term for bird. This reason for the name has been handed down: When Jupiter, moved by desire, had begun to love Nemesis, and couldn't persuade her to lie with him, he relieved his passion by the following plan. He bade Venus, in the form of an eagle, pursue him; he, changed to a swan, as if in flight from the eagle, took refuge with Nemesis and lighted in her lap. Nemesis did not thrust him away, but holding him in her arms, fell into a deep sleep. While she slept, Jupiter embraced her, and then flew away. Because he was seen by men flying high in the sky, they said he was put in the stars. To make this really true, Jupiter put the swan flying and the eagle pursuing in the sky. But Nemesis, as if wedded to the tribe of birds, when her months were ended, bore an egg. Mercury took it away and carried it to Sparta and threw it in Leda's lap. From it sprang Helen, who excelled all other girls in beauty. Leda called her her own daughter. Others say that Jove, in the form of a swan, lay with Leda. We shall leave the matter undecided. (Mary Ward 1960)

Almagest Ὅρνες (Bird).

id	Greek (Heiberg 1898)	English (Toomer 1984)	ident.
	Ὅρυιθος ἀστερισμός.	Constellation of Cygnus
1	ὁ ἐπὶ τοῦ στόματος.	The star on the beak	bet Cyg
2	ὁ τούτῳ ἐπόμενος καὶ ἐπὶ τῆς κεφαλῆς.	The one to the rear of this, on the head	phi Cyg
3	ὁ ἐν μέσῳ τῷ τραχήλῳ	The star in the middle of the neck	eta Cyg
4	ὁ ἐν τῷ στήθει	The star in the breast	gam Cyg
5	ὁ ἐν τῇ οὐρᾷ λαμπρός	The bright star in the tail	alf Cyg
6	ὁ ἐυ τῷ ἀγκῶνι τῆς δεξιᾶς πτέρυγος	The star in the bend of the right wing	del Cyg
7	τῶν ἐκ τῷ δεξιῷ ταρσῷ ἡ’ ὁ νότιος	The southernmost of the 3 in the right wing-feathers	tet Cyg
8	ὁ μέσος τῶν τριῶν	The middle one of the three	iot Cyg
9	ὁ βόρειος αὐτῶν καὶ ἐπ’ ἄκρου τοῦ ταρσοῦ	The northernmost of them, on the tip of the wing-feathers	kap Cyg
10	ὁ ἐπὶ τοῦ ἀγκῶνος τῆς ἀριστερᾶς πτέρυγος	The star on the bend of the left wing	eps Cyg
11	ὁ βορειότερος αὐτῶν καὶ ἐν μέσῃ τῇ αὐτῇ πτέρυγι	The star north of this, in the middle of the same wing	lam Cyg
12	ὁ ἐν ἄκρῳ τῷ ταρσῷ τῆς ἀριστερᾶς πτέρυγος	The star in the tip of the feathers of the left wing	zet Cyg
13	ὁ ἐπὶ τοῦ ἀριστεροῦ ποδός	The star on the left leg	nu Cyg
14	ὁ ἐπὶ τοῦ ἀριστεροῦ γόρατος.	The star on the left knee	xi Cyg
15	τῶν ἐν τῷ δεξιῷ ποῦὶ β ὁ προηγούμευος	The more advanced of the 2 stars in the right leg	omi1 Cyg
16	ὁ ἐπόμενος αὐτῶν	The one to the rear	omi2 Cyg
17	ὁ ἐπὶ τοῦ δεξιοῦ γόνατος νεφελοειδής.	The nebulous star on the right knee	ome Cyg
	ὁ ἀστέρες ἰς, ὥν β’ μεγέθους α, γ’ ἔ, δ’ 3, ε’ β.	17 stars, 1 of the second magnitude, 5 of the third, 9 of the fourth, 2 of the fifth
	Οἱ περὶ αὐτὸν ἀμόρφωτοι.	Stars around [Cygnus] outside the constellation
18	τῶν ὑπὸ τὴν ἀριστερὰν πτέρυγα ᾑ ὁ νοτιώτερος.	The southernmost of the 2 stars under the left wing	tau Cyg
19	ὁ βορειότερος αὐτῶν	The northernmost of them	sig Cyg
	ἀστέρες β μεγέθους ὀ΄.	2 stars of the fourth magnitude

Convex Hull for the stars inside Ornis (CC BY Youla Azkarrula).

Stars within the Constellation Area

id	Label	IAU design.	description	Vmag
1	Deneb	HIP 102098	Constellation lines	1.25
2	Sadr	HIP 100453	Constellation lines	2.23
3	Aljanah	HIP 102488	Constellation lines	2.48
4	Fawaris	HIP 97165	Constellation lines	2.87
5	Albireo	HIP 95947	Constellation lines (Vertex)	3.08
6	ζ Cygni	HIP 104732	Constellation lines (Vertex)	3.21
7	ξ Cygni	HIP 104060	Constellation lines (Vertex)	3.73
8	ι 2 Cygni	HIP 95853	Constellation lines	3.755
9	κ Cygni	HIP 94779	Constellation lines (Vertex)	3.76
10	ο1 Cyg	HIP 99675	Constellation lines	3.8
11	η Cygni	HIP 98110	Constellation lines	3.88
12	ν Cygni	HIP 103413	Constellation lines	3.94
13	ο2 Cyg	HIP 99848	Constellation lines	3.98
14	41 Cyg	HIP 101076	Inside the hull	4.01
15	52 Cyg	HIP 102453	Inside the hull	4.23
16	χ Cygni	HIP 97629	Inside the hull	4.24
17	39 Cyg	HIP 100587	Inside the hull	4.44
18	θ Cygni	HIP 96441	Constellation lines	4.48
19	λ Cygni	HIP 102589	Inside the hull	4.54
20	47 Cyg A	HIP 101474	Inside the hull	4.636
21	ϕ Cygni	HIP 96683	Constellation lines	4.673
22	8 Cyg	HIP 96052	Inside the hull	4.72
23	57 Cyg	HIP 103089	Inside the hull	4.77
24	30 Cyg	HIP 99639	Inside the hull	4.819
25	P Cyg	HIP 100044	Inside the hull	4.82
26	55 Cyg	HIP 102724	Inside the hull	4.86
27	15 Cyg	HIP 97118	Inside the hull	4.887
28	28 Cyg	HIP 99303	Inside the hull	4.93
29	T Cyg	HIP 102571	Inside the hull	4.93
30	ω 1 Cygni	HIP 101138	Constellation lines (Vertex)	4.936
31	22 Cyg	HIP 98068	Inside the hull	4.946
32	-	HIP 97295	Inside the hull	4.98
33	29 Cyg	HIP 99770	Inside the hull	4.99
34	26 Cyg	HIP 98571	Inside the hull	5.048
35	-	HIP 102843	Inside the hull	5.05
36	-	HIP 96825	Inside the hull	5.06
37	β 2 Cygni	HIP 95951	Inside the hull	5.11
38	19 Cyg	HIP 97630	Inside the hull	5.12
39	35 Cyg	HIP 100122	Inside the hull	5.162
40	-	HIP 96459	Inside the hull	5.169
41	25 Cyg	HIP 98425	Inside the hull	5.19
42	NGC 6871	NGC 6871	Inside the hull	5.2
43	61 Cyg A	HIP 104214	Inside the hull	5.21
44	-	HIP 99968	Inside the hull	5.236
45	-	HIP 96288	Inside the hull	5.336
46	-	HIP 99031	Inside the hull	5.37
47	14 Cyg	HIP 96693	Inside the hull	5.4
48	9 Cyg	HIP 96302	Inside the hull	5.407
49	-	HIP 98194	Inside the hull	5.455
50	-	HIP 103094	Inside the hull	5.462
51	-	HIP 103145	Inside the hull	5.47
52	-	HIP 98325	Inside the hull	5.502
53	-	HIP 96014	Inside the hull	5.54
54	-	HIP 103519	Inside the hull	5.547
55	-	HIP 100437	Inside the hull	5.572
56	36 Cyg	HIP 100108	Inside the hull	5.58
57	40 Cyg	HIP 100907	Inside the hull	5.62
58	-	HIP 97757	Inside the hull	5.63
59	49 Cyg	HIP 102066	Inside the hull	5.638
60	V1768 Cyg	HIP 98863	Inside the hull	5.65
61	-	HIP 102155	Inside the hull	5.664
62	-	HIP 101899	Inside the hull	5.673
63	V380 Cyg	HIP 97634	Inside the hull	5.68
64	-	HIP 99841	Inside the hull	5.698
65	-	HIP 96258	Inside the hull	5.7
66	-	HIP 104371A	Inside the hull	5.71
67	-	HIP 98767	Inside the hull	5.73
68	ι 1 Cygni	HIP 95656	Inside the hull	5.75
69	V2015 Cyg	HIP 101475	Inside the hull	5.769
70	-	HIP 97985	Inside the hull	5.781
71	DT Cyg	HIP 104185	Inside the hull	5.82
72	-	HIP 97376	Inside the hull	5.824
73	-	HIP 97081	Inside the hull	5.84
74	-	HIP 100069	Inside the hull	5.84
75	-	HIP 95352	Inside the hull	5.853
76	-	HIP 99889	Inside the hull	5.864
77	-	HIP 97774	Inside the hull	5.897
78	42 Cyg	HIP 101067	Inside the hull	5.899
79	-	HIP 100219	Inside the hull	5.9
80	V2119 Cyg	HIP 100574	Inside the hull	5.9
81	-	HIP 96977	Inside the hull	5.925
82	-	HIP 100501	Inside the hull	5.93
83	-	HIP 98383	Inside the hull	5.933
84	16 Cyg A	HIP 96895	Inside the hull	5.95
85	-	HR 7767	Inside the hull	5.958
86	V1743 Cyg	HIP 96198	Inside the hull	5.96
87	-	HIP 103371	Inside the hull	5.96
88	-	HIP 101986	Inside the hull	5.965
89	-	HIP 103734	Inside the hull	5.997
90	-	HIP 98143	Inside the hull	6.009
91	-	HIP 102033	Inside the hull	6.03
92	61 Cyg B	HIP 104217	Inside the hull	6.03
93	11 Cyg	HIP 96387	Inside the hull	6.034
94	-	HIP 97087	Inside the hull	6.053
95	V2093 Cyg	HIP 97651	Inside the hull	6.06
96	-	HIP 100486	Inside the hull	6.072
97	-	HIP 97028	Inside the hull	6.075
98	-	HIP 96724	Inside the hull	6.09
99	-	HIP 103894	Inside the hull	6.097
100	-	HIP 97242	Inside the hull	6.098
101	V* R Cyg	HD 185456	Inside the hull	6.1
102	-	HIP 97789	Inside the hull	6.1
103	-	HIP 97538	Inside the hull	6.117
104	-	HIP 97372	Inside the hull	6.12
105	-	HIP 98858	Inside the hull	6.14
106	-	HIP 99685	Inside the hull	6.14
107	-	HIP 99145	Inside the hull	6.141
108	-	HIP 103532	Inside the hull	6.156
109	-	HIP 96805	Inside the hull	6.16
110	-	HIP 98921	Inside the hull	6.17
111	-	HIP 97307	Inside the hull	6.179
112	16 Cyg	HIP 96901	Inside the hull	6.2
113	-	HIP 101756	Inside the hull	6.202
114	-	HIP 98563	Inside the hull	6.214
115	-	HIP 97700	Inside the hull	6.215
116	44 Cyg	HIP 101214	Inside the hull	6.216
117	-	HIP 96907	Inside the hull	6.22
118	-	HIP 100018	Inside the hull	6.22
119	* del Cyg B	* del Cyg B	Inside the hull	6.23
120	-	HIP 96706	Inside the hull	6.245
121	-	HIP 95953	Inside the hull	6.258
122	-	HIP 100016	Inside the hull	6.273
123	-	HIP 99893	Inside the hull	6.275
124	V819 Cyg	HIP 97845	Inside the hull	6.279
125	-	HIP 100515	Inside the hull	6.3
126	-	HIP 102530	Inside the hull	6.303
127	48 Cyg	HIP 101765	Inside the hull	6.304
128	-	HIP 103963	Inside the hull	6.324
129	NAME HD 193702AB	HIP 100268	Inside the hull	6.33
130	-	HIP 95673	Inside the hull	6.34
131	V2090 Cyg	HIP 97142	Inside the hull	6.35
132	-	HIP 97029	Inside the hull	6.36
133	-	HIP 100155	Inside the hull	6.36
134	V973 Cyg	HIP 97151	Inside the hull	6.37
135	-	HIP 98701	Inside the hull	6.378
136	-	HIP 97228	Inside the hull	6.379
137	-	HIP 100434	Inside the hull	6.383
138	-	HIP 100866	Inside the hull	6.398
139	-	HIP 102585	Inside the hull	6.411
140	-	HIP 96546	Inside the hull	6.42
141	-	HIP 96503	Inside the hull	6.43
142	-	HIP 97150	Inside the hull	6.44
143	-	HIP 102993	Inside the hull	6.44
144	-	HIP 103822	Inside the hull	6.44
145	V1773 Cyg	HIP 100142	Inside the hull	6.443
146	-	HIP 97572	Inside the hull	6.444
147	-	HIP 99929	Inside the hull	6.448
148	-	HIP 98253	Inside the hull	6.45
149	-	HIP 101133	Inside the hull	6.45
150	-	HIP 98146	Inside the hull	6.455
151	-	HIP 96396	Inside the hull	6.46
152	-	HIP 96572	Inside the hull	6.46
153	V1765 Cyg	HIP 97485	Inside the hull	6.463
154	-	HIP 99719	Inside the hull	6.464
155	-	HIP 103596	Inside the hull	6.465
156	-	HIP 101268	Inside the hull	6.467
157	X Cyg	HIP 102276	Inside the hull	6.47
158	V1584 Cyg	HIP 100250	Inside the hull	6.478
159	-	HIP 101768	Inside the hull	6.496
160	-	HIP 102062	Inside the hull	6.497
161	-	HIP 96491	Inside the hull	6.5
162	-	HIP 99653	Inside the hull	6.5

Transfer and Transformation of the Constellation

• 
  Cygnus in Fortin's Atlas Céleste, 3rd edition (1795).

Mythology

Greek

Eratosthenes reports that Zeus fell in love with Nemesis, the goddess of retributive justice or righteous anger. She wanted to remain a virgin and therefore fled from him. She once transformed herself into a swan, whereupon Zeus also transformed himself into a swan and thus succeeded in seducing her. He then flew energetically skyward, leaving behind the image of the magnificent animal form among the stars. The imprint in the star pattern depicts the bird flying, with its wings spread wide.

In the constellation Aquila, we present another version of the story, told by Hyginus in Roman times, according to which Zeus, in the form of a swan, allowed himself to be pursued by his eagle in order to find refuge in the bosom of Nemesis. However, the eagle in the sky does not pursue the swan, but they fly across the sky at the same time.

In any case, the result of this union is that Nemesis lays an egg. The egg later hatches into the beautiful Helen, who was the cause of the Trojan War. Helen is considered to be the daughter of Leda because the egg was given to Leda and Leda raised the girl.

References

• References (general)
• References (Babylonian)
• References (ancient Greco-Roman)
• References (medieval)