A prominent constellation of the northern sky, representing a lyre. Its brightest star is Vega. Beta Lyrae (Sheliak) is an eclipsing binary, the prototype of the Beta Lyrae stars; it varies between magnitudes 3.3 and 4.4 in a period of 12.9 days. It is also a double star, with a fainter component of magnitude 7.2. Delta Lyrae is a wide double, magnitudes 4.3 and 5.6, while Epsilon Lyrae is a famous quadruple star, the Double Double. Zeta Lyrae is another double star, magnitudes 4.4 and 5.7. RR Lyrae is the prototype of the RR Lyrae stars, an important class of pulsating variables. M57 is a well-known planetary nebula, the Ring Nebula. The Lyrid meteors radiate from the constellation every April.