Sirius. in the constellation, Canis Major, is the brightest star in the night sky (apparent magnitude -1.42).

The magnitude of a star or other celestial object is a number that measures its brightness. Apparent magnitude (m) of a celestial object is a number that measures its brightness as seen by an observer on Earth, and absolute magnitude is its actual brightness adjusted for distance. The brighter an object appears, the lower its magnitude value. The Sun, at apparent magnitude of −27, is the brightest object in the sky.