The brightest stars in the Northern Hemisphere's winter sky form the shape of the Winter Hexagon or Circle, that will help you locate 6 constellations.
Binary stars - a star system consisting of two stars - are extremely useful. They give all the information needed to measure mass of a star. Here is how.
When a year with 365 days starts on a Sunday, like 2023, it's inevitable Friday the 13th will occur twice. They will occur in January and October in 2023.
Wait, what? It's true. The sky's brightest star, Sirius aka the Dog Star, will come to within 1.6 degrees of the south celestial pole in the year 66270.
The Dog Star Sirius reaches its highest point in the sky around midnight every New Year's Eve. For this reason, it could also be called the New Year's star.
The longest days accompany the winter solstice. In December, a day - a whole cycle of day and night - is about half a minute longer than the average 24 hours.
You can see the Orion Nebula as a fuzzy spot in the sky using just your eyes. It's really a vast cloud in space where new stars are forming. Learn more.
Bruce McClure served as lead writer for EarthSky's popular Tonight pages from 2004 to 2021, when he opted for a much-deserved retirement. He's a sundial aficionado, whose love for the heavens has taken him to Lake Titicaca in Bolivia and sailing in the North Atlantic, where he earned his celestial navigation certificate through the School of Ocean Sailing and Navigation. He also wrote and hosted public astronomy programs and planetarium programs in and around his home in upstate New York.