Corona Borealis
Corona Borealis, a crown of seven stars tracing a half-circle. Here are the "Blaze Star," which may one day suddenly flare, and the tale of a princess's wedding garland.
Science
The scienceCorona Borealis is a small, lovely constellation whose seven stars trace an elegant half-circle (a crown) between Boötes and Hercules. Only the chief star Alphecca, the jewel of the crown, is bright, while the rest are faint, which makes the curve of the half-circle stand out all the more. This constellation holds a recurrent nova called the "Blaze Star" (T CrB), which is usually faint but suddenly erupts about every 80 years to blaze bright enough for the naked eye. It flared in 1866 and in 1946, and astronomers, believing the next eruption imminent, keep close watch on this constellation.
Mythology
How it became a constellationCorona Borealis is said to be the wedding garland of Ariadne, princess of Crete. By handing him a ball of thread, she helped the hero Theseus slay the Minotaur in the labyrinth and find his way safely out; yet Theseus abandoned her, leaving her alone on a strange island. Dionysus, god of wine, found her grieving and took her as his wife, and as a wedding gift crowned her with a golden diadem set with jewels. In time Dionysus flung that crown high into the sky, making it a constellation that shines forever.
Observing Guide
how to observe🔭 How to find it
On a summer night, look between Arcturus (the bright star of Boötes) and the Keystone of Hercules, and a small constellation catches your eye — seven stars tracing a graceful semicircle (a crown). Only the lead star Alphecca, the "jewel" of the semicircle, is truly bright, while the rest are faint — which actually makes the curve of that arc of dim stars stand out and easy to recognize.
✨ What to look for
Corona Borealis has almost no bright nebulae, clusters, or galaxies, so it offers little for deep-sky viewing — but it does harbor one very special star. That's T CrB, the recurrent nova called the "Blaze Star," which normally stays too faint to see but suddenly erupts about every 80 years, brightening enough to be visible to the naked eye. It flared in 1866 and 1946, and its next outburst is thought to be imminent, so amateur astronomers are keeping a close watch on this constellation.
📍 Where to see it (US · Canada · UK · Australia)
At +26° to +31° declination, Corona Borealis is well placed for northern observers, rising high on summer nights (May–August) from the US, Canada, and the UK, where its neat semicircle is easy to admire — and where a future outburst of the recurrent nova T CrB would be readily spotted. From Australia the Northern Crown appears lower in the northern sky during the southern winter, but is still comfortably visible.