Generalities: it is the  zodiacal constellation  pushed more southwards on the celestial vault. The solstice of December takes place in this constellation. It is a wide constellation, containing many stars of good brightness. The nucleus of the Milky Way is positioned in the same direction of the Sagittarius. The Sun crosses this constellation during the last decade of December and the first and the second decades of January.
 
Origin and mythology: it represent the Centaur Chiron, who was the tutor of Achilles and Jason.
 
Stars: there are seven stars under magnitude 3 and other nine under magnitude 4. The brightest star is called Kaus Australis of magnitude 1.85. Its color is white and its distance is 85 light-years. Near to this star there are also Kaus Borealis and Kaus Medium. The second star of this constellation is called Nunki, of magnitude 2.02 and blue-white color.
 
Table of stars brighter than magnitude 3.5
 

Star	Proper name	Magnitude	Spectrum	Colour	Distance (light-years)	Notes
Epsilon	Kaus Australis	1.85	B9	white	85
Sigma	Nunki	2.02	B3	blue	209
Zeta	Ascella	2.59	A2	white	78
Delta	Kaus Medium	2.70	K2	orange	81
Lambda	Kaus Borealis	2.81	K2	orange	98
Pi	Albaldah	2.89	F2	white-yellow	310
Gamma	Alnasr	2.99	K0	orange	117
Eta		3.11	M3	red	425
Phi		3.17	B8	white	245
Tau		3.32	K1	orange	130

Other objects: Sagittarius shows a lot of interesting deep sky.  Three nebulae are very famous: M20 (Trifid Nebula), M17 (Omega Nebula), and M8, the brightest (Lagoon Nebula). This constellation contains many open clusters: M18, M21, M23, M24 e M25 and globular clusters: M22, one of the most beautiful in the sky, M28, M54, M55, M69, M70, M75.

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