A pair of dogs trots across the night skies of winter: Sirius, the Dog Star, and Procyon, the little dog star. The names indicate that they’re the brightest stars of the constellations Canis Major, the big dog, and Canis Minor, the little dog.

The name “Sirius” means “glowing” or “scorching.” The first of those meanings refers to Sirius’s brilliance — it’s the brightest star in all the night sky. And the second refers to the time of year it made its first appearance in the morning sky when it was named — at the start of the hottest part of summer. In fact, that’s why we call that part of the year the Dog Days.

Procyon means “before the dog.” From most of the northern hemisphere, it rises a little earlier than Sirius does, so it precedes the Dog Star into the sky.

Sirius and Procyon are remarkably similar. They’re about the same distance from Earth, and each consists of two stars. The main star in each system is bigger and heavier than the Sun, and a good bit brighter. And the other star in each system is a white dwarf — the hot but tiny corpse of a once-bright star.

Sirius and Procyon are low in the east and southeast as the sky gets fully dark. Because they’re so bright, though, they’re quite easy to spot. Brilliant Sirius is directly below Orion’s Belt — a short line of three bright stars. Procyon is off to the upper left of Sirius — the little dog leading the big dog across the night sky.

Script by Damond Benningfield