Star
The Sun has an apparent magnitude of −26.7, but its absolute magnitude is only +4.83. Sirius, the brightest star in the night sky as seen from Earth, is approximately 23 times more luminous than the Sun, while Canopus, the second brightest star in the night sky with an absolute magnitude of −5.53, is approximately 14,000 times more luminous than the Sun. Despite Canopus being vastly more luminous than Sirius, however, Sirius appears brighter than Canopus. This is because Sirius is merely 8.6 light-years from the Earth, while Canopus is much farther away at a distance of 310 light-years.
Royal stars
The four dominant stars have an apparent magnitude–1.5 or brighter. The reason why they are called "Royal" is that they appear to stand aside from the other stars in the sky. The four stars, Aldebaran, Regulus, Antares, Fomalhaut, are the brightest stars in their constellations and among the 25–brightest stars in the night sky. The Persians considered these stars to be the four guardians of the heavens. They marked the seasonal changes and marked the equinoxes and solstices.