Winter Triangle

It is an imaginary isosceles triangle[a] drawn on the celestial sphere, with its defining vertices at Sirius, Betelgeuse, and Procyon, the primary stars in the three constellations of Canis Major, Orion, and Canis Minor, respectively.

In the spring the winter triangle is visible early in the evening to the West before its stars set below the horizon.

From the southern hemisphere it appears upside down and lower in the sky during the summer months.

[2] The Winter Triangle surrounds most of the faint constellation Monoceros, although its brightest stars are of fourth magnitude and hardly noticeable to the naked eye.

The other bright stars of the winter sky lie around the triangle: Orion including Rigel; Aldebaran in Taurus; Castor and Pollux in Gemini; and Capella in Auriga.