Canis Major

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

One of the 88 IAU constellations. This is the (one and only) constellation of the Dog in ancient Greek astronomy.

Orion-Group of constellations on the Kugel Globe, drawing and animated GIF by SMH 2025.

Etymology and History

In Hellenistic times, Greek astronomy had only one constellation, the Dog, so there was no need to distinguish between a large and a small dog. According to Eratosthenes, this dog had the bright star Sirius on its tongue. Ptolemy in Roman times placed it on the dog's snout.

What is interesting about Sirius, however, is that today we use the Greek proper name from Hellenistic times. Ptolemy in Roman times called the brightest star of the constellation ‘the Dog’.

Origin of Constellation

Greco-Roman

Aratos

[326] Such a guardian, too, beneath his towering back is seen to stand on his hind legs, the Dog [Canis Major] starenwrought, yet not clearly marked in all his form, but right by his belly he shows dark. The tip of his terrible jaw is marked by a star that keenest of all blazes with a searing flame and him men call Seirius. When he rises with the Sun, no longer do the trees deceive him by the feeble freshness of their leaves. For easily with his keen glance he pierces their ranks, and to some he gives strength but of other s he blights the bark utterly. Of him too at this setting are we aware, but the other stars of the Dog are set round with fainter light to mark his legs.

[594?] Up rises the Hydra’s head and the bright-eyed Hare and Procyon and the forefeet of the flaming dog.

[675?] With them the Lyre of Hermes and Cepheus to his breast drive up from the Eastern Ocean, what time all the rays of the mighty Dog are sinking and all of Orion setting, yea, all the Hare, which the Dog pursues in an unending race.

(Kidd 1997)

Almagest Κύων

id	Greek (Heiberg 1898)	English (Toomer 1984)	ident.
	Κυνὸς ἀστερισμός	Constellation of the Dog
1	ἐν τῷ στόματι λαμπρότατος καλούμενος Κύωυ καὶ ὑπόκιρρος.	The star in the mouth, the brightest, which is called 'the Dog' and is reddish	alf CMa
2	ὁ ἐπὶ τῶν ὡτοη.	The star on the ears	tet CMa
3	ὁ ἐπὶ τῆς κεφαλῆ	The star on the head	gam CMa
4	τῶν ἐκ τῷ τραχήλῳ β ὁ βόρειος	The northernrriost of the 2 stars in the neck	iot CMa
5	ὁ φόσιος αὐτῶν	The southernmost of them	pi CMa
6	ὁ ἐπὶ τοῦ στήθους.	The star on the chest	nu3 CMa
7	τῶν ἐπὶ τοῦ δεξιοῦ γόνατος β ὁ βόρειος.	The northernmost of the 2 stars on the right knee	nu2 CMa
8	ὁ νοτιώτερος αὐτῶν.	The southernmost of them	bet CMa
9	ὁ ἐπ’ ἄκρῳ τῷ ἐμπροσθίῳ ποδί	The star on the end of the front leg	xi1 CMa
10	τῶν ἐν τῷ ἀριστερῷ γόνατι β ὁ προηγούμευος.	The more advanced of the 2 stars in the left knee	xi2 CMa
11	ὁ ὁ ἐπόμενος αὐτῶν	The rearmost of them	omi2 CMa
12	τῶν ἐν τῷ ἀριστερῷ ὤμῳ β’ ὁ ἑπόμενος;	The rearmost of the 2 stars in the left shoulder	omi1 CMa
13	ὁ προηγούμενος αὐτῶν	The more advanced of them	del CMa
14	ὁ ἐν τῇ ἐκφύσει τοῦ ἀριστεροῦ μηροῦ.	The star in the place where the 1eft thigh joins [the body)	del CMa
15	ὁ ὑπὸ τὴν κοιλίαν ἐν τοῦς μεσομήροις	The star below the belly, in the middle of the thighs	eps CMa
16	ὁ ἐπὶ τῆς ἀγκύλης τοῦ δεξιοῦ ποδός	The star on the joint of the right leg	kap CMa
17	ὁ ἐπ’ ἄκρου τοῦ δεξιοῦ ποδός.	The star on the end of the right leg	zet CMa
18	ὁ ἐπὶ τῆς οὐρᾶς	The star on the tail	eta CMa
	ἀστέρες τῆ, ὥν αἱ μεγέθους ἂ, γ’ ἓ, δ’ ἓ, ε’ ξ.	{18 stars, 1 of the first magnitude, 5 of the third, 5 ofthe fourth, 7 of the fifth}
	Οἱ περὶ τὸν Κύνα ἀμόρφωτοι.
19	ὁ ἀπ’ ἄρκτου τῆς κορυφῆς τοῦ Κυνός.	The star to the north of the top of The Dog	22 Mon
20	τῶν ὑπὸ τοὺς ὀπισθίους πόδας ὡς ἐπ’ εὐθείας ὁ ὁ νοτιώτατος.	The southernmost ofthe 4 stars almost on a straight line under the hind legs	θ Col
21	ὁ τούτου βορειότερος.	The one north of this	κ Col
22	ὁ ἔτι τούτου βορειότερος.	The one north again of this	δ Col
23	ὁ λοιπὸς καὶ βορειότερος τῶν δ	The last and northernmost of the 4	λ CMa
24	τῶν πρὸς δυσμὰς τοῦς τέσσαρσιη ὡς ἐπ’ εὐθείας γ ὁ προἠγούμενος	The most advanced ofthe 3 stars almost on a straightline to the west of the [ above] four	μ Col
25	ὁ μέσος αὐτῶν	The middle one	λ Col
26	ὁ ἑπόμευος τῶν τριῶν.	The rearmost of the three	γ Col
27	τῶν ὑπὸ τούτους β λαμπρῶν ὁ ἐπόμευος.	The rearmost of thc 2 bright stars under these	β Col
28	ὁ προηγούμενος αὐτῶν.	The more advanccd of them	α Col
29	ὁ λοιπὸς καὶ νοτιώτερος τῶν προειρημένων.	The last star, to the south of the abovc	ε Col
all	ἀστέρες ἱα, ὥν β’ μεγέθους β, δ’ 9.	{11 stars, 2 of the second magnitude, 9 of the fourth)

Transfer and Transformation of the Constellation

• 

  Canis Major and Canis Minor on the Kugel Globe (1st c.BCE), drawing by SMH 2021.

• 

  Canis Major on the Mainz Globe following Orion (drawing by SMH 2021)

• 

  Canis Major on Mercator (1551)

• 

  Canis Major in Bayer's Uranometria (1603)

• 

  Canis Major in Hevelius (1690)

• 

  Canis Major in Flamsteed/ Fortin (1776)

• 

  Canis Major in Jamieson (1822)

• 

  Canis Major in Hall (1825)

References

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