The Winter Triangle meets the ‘Mars Triangle’ in the night sky this month

We’re now just past the midpoint of astronomical winter — that moment marking the midway point between December’s winter solstice and March’s vernal equinox. That moment took place at 4:11 p.m. Eastern Time on Feb. 3. And as darkness falls this week, we have what many refer to as the “Winter Triangle” dominating the southeast sky.

This large, nearly equilateral triangle is composed of three of the brightest stars in the sky, each belonging to its own constellation. The brightest is the bluish-white star Sirius (magnitude -1.45), in Canis Major the Big Dog; the brightest of all naked-eye stars. Next in brightness is yellow-white Procyon (magnitude +0.37) in Canis Minor, the Little Dog. The name Procyon is derived from the Ancient Greek, meaning “before the dog”, since it precedes the “Dog Star” Sirius as it travels across the sky due to the rotation of our Earth. From mid-northern latitudes, Procyon rises above the east-northeast horizon about 25 minutes before the more dazzling Sirius emerges above the east-southeast horizon. Finally, there is ruddy Betelgeuse (magnitude +0.48), in Orion the Hunter, a star well-known for its irregular variability in brightness. These stars appear in that order, as the twilight sky grows dark. This stellar trio is crossing the meridian at around 9 p.m. If you wait until around 2 a.m., the Triangle will have begun setting in the west-southwest.