T Coronae Borealis (T CrB), popularly known as the “Blaze Star,” is surely on the verge of a rare and dramatic brightening.
This recurrent nova, located approximately 3,000 light-years away in the constellation Corona Borealis, was predicted to explode in a thermonuclear eruption between April and September 2024. For sky-watchers, the failure of the star to suddenly become visible to the naked eye during winter — for the first time since 1946 — is good news because, since September, it’s not been visible until the very early hours.
That’s changing as its host constellation, Corona Borealis, begins to rise after dark. With a recurrent nova explosion, a very rare event, it’s worth finding its patch of sky now in the night sky so you know where to look — and are more easily impressed — when it briefly becomes visible.
When to see the ‘Blaze Star’
In March 2025, Corona Borealis will rise in the eastern sky about three hours after sunset. It will become easily visible around four hours after sunset.
So, while it may necessitate staying up late, it’s an excellent opportunity for skywatchers to witness the sudden brightening of T CrB — if it happens — before the star fades back into obscurity for another 80 years. With each passing month, it will rise two hours earlier, so it will very soon be an easy nighttime object.
Where to see the ‘Blaze Star’
T CrB will be positioned between two of the brightest stars in the night sky: Vega, rising in the northeast, and Arcturus, rising in the east.
If you can’t immediately find those two stars, finding the “Blaze Star” is most easily done by first locating the Big Dipper/Plough, one of the most recognizable patterns in the night sky. Follow the arc of its handle to Arcturus, the fourth brightest star in the sky, shining with an orange hue in the Boötes constellation above the east. Next, locate Vega, a brilliant blue-white star in the Lyra constellation, above north-east.
Corona Borealis, a delicate semicircle of seven stars, lies between them. Within this constellation, the “Blaze Star” will briefly outshine its neighbors, appearing as an extra-bright star just outside the crescent, close to a star called Epsilon CrB, the constellation’s fifth brightest.
How to find the ‘Blaze Star’ using a telescope
Most astronomy and planetarium software programs and apps have T CrB in their catalogs, including Stellarium.
For astrophotographers and owners of smart telescopes that don’t have T CrB in their catalogs (such as the ZWO SeeStar S50), instead lock on to IC4587, an elliptical galaxy in Corona Borealis that’s very close to T CrB.
If you’re looking for a telescope or binoculars to observe the blaze star, our guides for the best binoculars deals and the best telescope deals now can help.
Why find the ‘Blaze Star’ now?
When T CrB suddenly goes nova, it’s not going to “light up the night sky,” as some media will undoubtedly report. Since it’s going to leap in brightness from about mag. +10 to around mag. +2 — about the same as Polaris, the North Star — you’re going to have to find this “guest star” yourself, so it makes sense to familiarize yourself with its position in advance.
What the ‘Blaze Star’ really is
T CrB is two stars. Every 78 to 80 years, the white dwarf in this binary system accumulates enough material from its companion red giant star to trigger a thermonuclear explosion.
This process causes the star to brighten by more than 1,000 times, creating the illusion of a “new star” in the sky.
Its dimming during 2023 led to the prediction that it was about to go nova. That didn’t happen, but that only means that its explosion is likely imminent.
Since one of the most fascinating stellar phenomena of our time will only be visible for about a week, find T CrB in March — and don’t let it out of your sight.
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