The brightest star visible from Earth is Sirius, located in the Canis Major constellation. There are many very bright stars in the night sky that are visible from Earth, and as the moon makes its orbit it does pass near or in front of several of these.
The brightness of stars viewable from Earth is measured using a scale known as "magnitude." Given that stars can be at an infinite number of different distances from the Earth, their magnitudes are usually charted as both their apparent brightness and their absolute brightness. Apparent magnitude refers to the observable light as seen from Earth. Absolute magnitude is a measurement based on a standard distance