Double Star in Canes Venatici

Cor Caroli is the brightest star in the small constellation Canes Venactici (the hunting dogs). It is easy to find below the handle of the Big Dipper. Through a telescope, Cor Caroli can be seen as a wide double star, with a bright white primary star and a dimmer companion. The primary star is a variable that changes slightly in brightness over a period of about 5.5 days.

The distance between these two stars is about 650 astronomical units (that is, 650 times the average distance between the Sun and the Earth).

Magnitudes 2.8, 5.6
Separation 19.6"
Distance (light yrs) 110
Right Ascension 12:56.0
Declination +38 19

Image details:  17 images, each 1/20 second at ISO 200, taken with a Canon 400D camera through a Meade 12” telescope at f/6.7. 

April 2010