Xi Ursae Majoris, also known as Alula Australis, is a double star in Ursa Major. It’s best viewed in winter. This binary system is notable for many reasons: It’s a close binary system to earth — only 25 light years away. It was the first binary system to be discovered. William Herschel discovered it inContinueContinue reading “Xi Ursae Majoris: A Binary Star Close to Home”
Category Archives: Double/Multiple Stars
24 Comae Berenices: An Amber and Sapphire Double Graces the Spring Sky
24 Comae Berenices is a pretty double star. This striking contrast of the primary amber star against the smaller bluish star makes this pair a worth target in springtime skies.
Cor Caroli: A Binary Star with a Heart of a King
Cor Caroli is a double star in the constellation Canes Venatici. It’s best viewed in spring. The primary star, at a magnitude of 2.9, shines a white blue, while the dimmer companion, at a magnitude of 5.5, shines a warm yellow. This contrast of color makes for an attractive pair in the warming spring sky.
Castor: You Are Not Just Seeing Double
Known as one of the brightest stars in the sky and twin of Pollux, Castor is a bluish-white double star in the constellation of Gemini.
Zeta Cancri: A Multiple Star System in Cancer
Zeta Cancri is a multiple star system in the constellation Cancer. It’s best viewed in the spring. For many years, astronomers believed Zeta Cancri to be a triple star system, though now it has been found to be a quadruple system. According to Jim Kaller, the close binary pair (known as Zeta Cancri A andContinueContinue reading “Zeta Cancri: A Multiple Star System in Cancer”
Delta Geminorum (Wasat): A Star With a Unique History
Wasat is the primary star in a triple star system in the constellation Gemini. It’s best viewed in the winter. At magnitude +3.5, Wasat is not difficult to find under suburban skies. As you look at Wasat, you’re looking at a historical area of the night sky. In February 1930, Kansas farmboy-turned-astronomer Clyde Tombaugh discoveredContinueContinue reading “Delta Geminorum (Wasat): A Star With a Unique History”
Struve 747: A Pair of Light Blue Topaz Stars
With many competing targets in the Orion neighborhood, it may be easy to overlook notable double stars such as Rigel and Struve 747 (also known by HR 1887). Struve 747 is a 4th magnitude double star in Orion and a worthy target on any winter night. When observing the pair, you’ll notice they are prettyContinueContinue reading “Struve 747: A Pair of Light Blue Topaz Stars”
Rigel: Shine On, You Crazy Diamond
Rigel is one of the most popular stars in the sky as it marks the foot of thee constellation Orion. It is a blue-white supergiant star, and when you look at it closer, you’ll find a small companion star floating in Rigel’s glow.
The Garden Astronomer 