A constellation of the zodiac, representing a scorpion. The Sun passes through Scorpius for a week at the end of November. Its brightest star is Antares. Beta Scorpii (Acrab) is a double star of magnitudes 2.6 and 4.9. Another prominent double is the naked-eye pair Zeta Scorpii, magnitudes 3.6 and 4.8. Nu Scorpii is a notable quadruple star. M4, a 6th-magnitude globular cluster nearly ½° wide, is 7000 l.y. away, one of the closest globulars to us. M6 is a 4th-magnitude open cluster ¼° wide, and M7 is a 3rd-magnitude open cluster more than 1° across. Scorpius X-1 is the brightest X-ray source in the sky.