Generalities: it is a southern constellation, which includes two stars of average brightness. Its zenith at midnight takes place in June.

Origins and mythology: the Altar is one of the original constellations defined by Tolomeo. It isn't associated to any particular mythological circumstances.

Stars: the Altar shows two stars under  magnitude 3, seven altogether under  magnitude 4. The brightest one has magnitude 2.85, orange color and a rather elevated distance (780 light-years). The second star, named Choo is white-blue,  has magnitude 2.95 and  is  190 light-years far.

 
Table of stars brighter than magnitude 3.5
 

Star	Proper name	Magnitude	Spectrum	Color	Distance (light-years)	Notes
Beta		2.85	K3	orange	780
Alpha	Choo	2.95	B3	white-blue	190
Zeta		3.13	K5	orange-red	137
Gamma		3.34	B1	blue	1075
Delta		3.62	B8	white	95
Theta		3.66	B1	blue	1550
Eta		3.76	K5	orange-red	190

Other objects: it contains some globular clusters of some interest.
 

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