Enjoying EarthSky? Subscribe.

253,132 subscribers and counting ...

Star of the week: Alphecca

Alphecca. Gemma. Alpha Coronae Borealis or simply Alpha Cor Bor. They’re all names for one star – the brightest star in the constellation Northern Crown.

The Guardians of the Pole

Kochab and Pherkad – 2 stars in the Little Dipper – are called Guardians of the Pole. How to find them and more.

Is Zubeneschamali green?

Although some scientists claim stars can’t look green, many stargazers will swear that Zubeneschamali proves otherwise.

Zubenelgenubi is Libra’s alpha star

It’s now Libra’s alpha star. But Zubenelgenubi is an Arabic name indicating that this star was once perceived as the Southern Claw of Scorpius the Scorpion.

Polaris is the North Star

The entire northern sky wheels around Polaris. But it’s not the brightest star in the sky. In fact, Polaris ranks only 50th in brightness.

Alpha Centauri system, closest to sun

We see this star system as a single star, but it’s really 3 stars. Of the 3, Proxima is closer to our sun than any other known star.

Arcturus cuts through galaxy’s disk

Arcturus, a red giant, looks orange to the eye. It’s the brightest star on the northern half of Earth’s sky dome.

Thuban is a former Pole Star

Thuban was the Pole Star some 5,000 years ago, when the Egyptians were building the pyramids.

Hadar is a southern pointer star

Hadar, aka Beta Centauri, joins Alpha Centauri in pointing to the Southern Cross. It’s a triple system. Two of its stars will someday become nearby supernovae.

Spica is a whirling double star

Spica, the brightest star in the constellation Virgo, is a whirling double star. How to see it in your sky.

Mizar and Alcor, famous double star

Find Mizar and its fainter companion star Alcor in the Big Dipper’s handle.

Cor Caroli, the Heart of Charles

Cor Caroli is a binary star and the brightest star in the northern constellation Canes Venatici, the Hunting Dogs.

Mimosa, 2nd-brightest in Southern Cross

To glimpse Mimosa, you need to be at the latitude of New Orleans, Cairo or New Delhi. From the southern hemisphere, Mimosa is a prominent and beloved star.

Acrux, brightest star in Southern Cross

You have far south on Earth’s globe to see the Southern Cross. Bluish Acrux, aka Alpha Crucis, is its brightest star.

Regulus: Heart of the Lion

Meet Regulus, brightest star in the constellation Leo the Lion.

Alphard is the Snake’s Heart

The star Alphard is the Heart of the Snake in constellation Hydra. Look for Alphard in the evening sky in March, April, and May.

Pollux: The brighter Twin star

Close together in the sky, Pollux and its brother star Castor are easy to compare. Pollux is brighter and golden in color, while Castor is fainter and white.

Procyon is the Little Dog Star

The Dog Star, Sirius, is easy to spot because it’s the sky’s brightest star. Procyon – the other Dog Star – is near its brighter brother on the sky’s dome.

Castor is 6 stars in one

Castor is one of 2 bright stars in the constellation Gemini the Twins. It appears as a single star, but it’s actually a multiple star system.

Sirius is Dog Star and brightest star

Sirius – the Dog Star – is the sky’s brightest star. It’s very easy to spot on winter and spring evenings.