Enjoying EarthSky? Subscribe.

245,565 subscribers and counting ...

Larry Sessions

Star of the week: Castor

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.

Jupiter starts retrograde on February 6

The best time to look for Jupiter is just ahead. Its retrograde motion begins today. A bright star, Spica in the constellation Virgo, is right next to it.

Second-brightest star Canopus

Canopus is the 2nd-brightest star in the sky, and it’s easy to spot on February evenings, if …

See a faint star cluster near bright Sirius

Sirius is easy to find. It’s the sky’s brightest star. If you have binoculars and a dark location, look near it for the star cluster M41.

Capella is 2 golden stars

We see Capella as the brightest star in the constellation Auriga the Charioteer. It’s actually 2 stars, each with a golden color similar to our sun.

Rigel in Orion is blue-white

Blue-white Rigel, in the constellation Orion, is one of the brightest stars in the night sky. It’s about twice as hot, and 40,000 times brighter, than our sun.

Leap second to be added December 31

Delay those New Year’s plans. World timekeepers will add a leap second just before midnight on December 31, 2016.

Aldebaran is the Bull’s fiery eye

Aldebaran – brightest star in the constellation Taurus the Bull – is huge! If it were in our sun’s place, its surface would extend almost to the orbit of Mercury.

Can you see stars’ different colors?

Late December is the perfect time for noticing the colors of the stars. Never noticed them? Our sky chart can help guide your eye.

Betelgeuse will explode someday

Someday, the star Betelgeuse will run out of fuel, collapse under its own weight, and then rebound in a spectacular supernova explosion. Someday … but probably not soon.