145 Canis Majoris: Winter’s Beautiful Version of Albireo

There’s something poetic about comparing winter’s 145 Canis Majoris (145 CMa) to summer’s Albireo. While Albireo is celebrated for its striking colors and brilliance on summer nights, 145 CMa offers a subtler yet captivating spectacle for crisp winter nights. Skygazers seeking its beauty must explore the rich depths of Canis Major, just as John Herschel did in 1837 when he first recorded the double star.

Double stars with contrasting colors, like 145 CMa and Albireo, create a stunning visual effect that captivates observers. In the case of 145 CMa, the bright primary star shines at magnitude +5.0 with a warm orange-yellow hue, while its nearby secondary star glows with an aqua tint. Adding to their appeal, the two stars are separated by a comfortable 26.4 arcseconds, making the pair an accessible winter jewel for most backyard stargazers.

My Observations

This is undoubtedly one of the best double stars in the winter sky. To me, the primary star appears more yellow than orange, but I’ve come across other observers who describe it as clearly orange—or even red. This could be due to the varying atmospheric conditions experienced by different observers. Using my 12mm eyepiece on my 8-inch scope, I can easily split the pair, providing a pleasant view of this sparkling gem.

Key Stats

Constellation	Canis Major
Best Viewing	Winter
Visual Magnitude	+5.0 | +5.8
Separation	26.4″
Position Angle	47.9°
Spectral Class	K0 & F0
Milky Way Location	Orion Spur
My Viewing Grade	A+
Designations	145 CMa, SAO 173349, HR 2764, HD 56577, HIP 35210, G Canis Majoris

Sources and Notes

Sketch by Wayne McGraw