Variable Stars

All stars appear to twinkle due to our ever-turbulent atmosphere. But some truly do rise and fall in brightness. These so-called variable stars seem to pulsate — either because a star is in a binary system and its companion often eclipses it, or because the star itself periodically swells and shrinks, pulsating in brightness. Polaris, the north star known for being so constant, is itself a variable star.

Sky & Telescope can help you monitor these dancing stars, providing valuable research to astronomy. For more than a century amateur astronomers have helped scientists monitor these stars, collecting nearly all the brightness data on record for hundreds of variable stars.

Cetus — Till Credner

The Inconstant Star

The joys of observing variable stars are predictably wonderful. Learn about these inconstant stars which are consistently delightful.

Bright Supernova Beckons

Bright Supernova Erupts in NGC 5643 in Lupus

A recently discovered supernova in Lupus now shines around magnitude +11.5, bright enough to see in a modest telescope. With photos and maps, we'll get you there. I wished I lived in Georgia and not just for the peach trees and warmer weather. No, I'd be able to get up early tomorrow morning to marvel at…

Chi Cygni’s Record-Breaking Maximum

The red, Mira-type variable star Chi Cygni has had a very unusual maximum. It's one of the brightest such variables to begin with (typically peaking at about magnitude 5.2), but in late July and early August 2006, it peaked at about magnitude 3.8.

Nova Delphini 1967

Nova Hunters

Few observers have spotted an ever-elusive "new" star. Fewer still have done it twice. Observing styles and techniques are as varied as the searchers themselves.