Astronomy

Arcturus (alpha Boötis) is the brightest star north of the celestial equator and only Sirius outshines it from UK shores. Dominating the short, late-spring nights is Arcturus, the brightest star of the northern hemisphere sky and the sentinel of spring. It’s the brilliant leader of the constellation of Boötes, the Herdsman, or Bear Keeper, an area of the night sky that’s bereft of bright deep-sky objects, including no Messier-designated targets. Don’t you think then that it’s rather fitting that otherwise uninspiring Boötes has been handed the distinct honour of hosting Arcturus, as well as several superb double stars, including the beautifully formed and named Pulcherrima (Izar, epsilon Boötis).  Arrive at Arcturus Arcturus is a magnificent naked eye star, shining at magnitude –0.04 – o...

It’s been a momentous May for skywatchers around the world. First the big auroral event of May 10-11, next a flaming space rock entering over Spain and Portugal. The inbound object was captured by ground-based cameras and the MeteoSat Third Generation Imager in geostationary orbit. The incoming meteor dazzled viewers across both countries as it sped across the skies at 160,000 km/hour. Of course, social media came alive with speculation about what was burning up in the atmosphere. Most people thought it was a piece of space rock from an asteroid. European Space Agency members of the Planetary Defence Office immediately began analyzing images and data to figure out the composition of the impactor. Now it seems more likely the chunk of space debris came from a comet. They used other data a...

Messier 3 is a great globular cluster of the late-spring sky. Image: Adam Block. During late spring or early summer—whichever term you choose, likely depending on how fine the weather has been—is the best time to seek out and observe globular clusters, which are among the most striking and impressive categories of deep-sky objects. Globular clusters are densely-packed, near spherical collections of ancient stars that populate mainly the extended outer halo of our galaxy. They are believed to have formed in the very early life of our Galaxy, over 11 billions years ago; Messier 3 is thought to be 11.4 billion years old. Astounding star densities exist inside even run-of-the-mill globulars; on average, 0.4 stars per cubic parsec (a parsec is equal to 3.26 light years), rising to 100 to 1,000...