LAKE COUNTY, Calif. – As winter gives way to spring, March shows us the greatest number of bright stars in the sky.

It’s time for a bright star tour!

The brightness of a star is measured by its magnitude. Magnitude is a scale. The lower the number on the scale, the brighter the object.

Very bright objects, such as the Sun and the Moon, register -26 and -12.5 on the scale, respectively.

Out of the 22 brightest stars in the sky, this month has nine of them. They are shown on our star chart.

Sirius is the brightest star in the sky at magnitude -1.46. It’s in the constellation Canis Major, the Big Dog.

Capella is the next brightest at magnitude 0.08.

The remaining stars are Rigel (0.12), Procyon (0.38), Betelgeuse (0.5) Aldebaran (0.85), Pollux (1.14), Regulus (1.35) and Castor (1.57).

What makes one star brighter than another? It’s a combination of the star’s age, size and how far away it is.

Sirius, the brightest star, is relatively small, but is young and close (8.6 light years).

In contrast, Betelgeuse is old, far away (520 light years) and huge (700 million miles in diameter).

John Zimmerman is a resident of Lake County and has been an amateur astronomer for more than 50 years. For more information about Astronomy and local resources, visit his website at www.lakecountyskies.com .