2025, May 26: Blaze Star, Where are You?

May 26, 2025: The Blaze Star, known as T Coronae Borealis, is expected to erupt.  Where is it in the sky?

Venus, December 10, 2020
2020, December 10: Morning Star Venus is in front of the stars of Libra.

by Jeffrey L. Hunt

Chicago, Illinois: Sunrise, 5:21 a.m. CDT; Sunset, 8:15 p.m. CDT.  Check local sources for sunrise and sunset times. Times are calculated by the US Naval Observatory’s MICA computer program.

Related Articles

Venus Summary Article
VENUS AS A MORNING STAR, 2025

Arcturus Leads to Blaze Star

Bright Arcturus, May 26, 2025
2025, May 26: Two hours after sunset, Arcturus is high in the south-southeastern sky.

Step outside after the end of evening twilight, about two hours after sundown, and look high in the south for topaz Arcturus, the brightest star in the northern half of the sky. It is 37 light years away and shines with an intensity of 100 suns.

The star’s name means “bear guard” and along with its constellation, Boötes, they chase the Great Bear (Big Dipper).  At this hour the dipper is high in the northwest, nearly overhead.

In Chicago, Arcturus has connections to great events in the city. The 1933 World’s Fair used Arcturus’ light to energize photoelectric cells attached at the eyepieces of four telescopes in the eastern U.S. – Yerkes Observatory, University of Illinois, Allegheny Observatory, and Harvard Observatory – to switch on a searchlight that signaled the beginning of the fair.

Arcturus was thought to be 40 light years away.  The 1933 fair was 40 years after the 1893 Columbian Exposition, which also occurred in Chicago.

There is a competing story about how the searchlight was signaled from the light of a telescope set up on the fairgrounds.

Blaze Star with Corona Borealis

Corona Borealis, the Northern Crown, is east of Boötes. Its seven stars nearly fit into the same binocular field of view.  Optical assistance is needed to see the constellation for suburban sky watchers.  Its brightest star is named Gemma or Alphecca, meaning “the broken or fractured one.”  The constellation was also known as “the bowl of beggars,” according to George Davis’ summary Pronunciations, Derivations, and Meanings of a Selected List of Star Names.

A binocular view of T Coronae Borealis
Chart Caption – 2025, May 26: Through a binocular T Coronae Borealis’ (T CrB) location is shown relative to Gemma, the constellation’s brightest star, and Epsilon Corona Borealis (ε CrB).

Throughout the year, the popular press has hyped a star named T Coronae Borealis which is expected to brighten.  Known as the “Blaze Star, T Coronae is known as a recurrent nova, which is part of a double or binary star system, two stars that revolve around a common center of gravity.

The smaller, dense star, such as a white dwarf, draws toward its surface the outer layers of the nearby larger, redder component star.  The debris collects on a disk of debris – that could be visualized to look like Saturn’s rings.  As the material collects it is heated and begins to glow in colors – such as ultraviolet – that are seen by satellites above the filtering effects of Earth’s atmosphere.  When the temperatures increase to millions of degrees, a brief sudden flare of nuclear fusion occurs that continues from a few hours to a few days.  The star temporarily flares or blazes with an increase of brightness.

Blaze Star is Due

T Coronae’s cycle is nearly 80 years.  With the last eruption occurring in 1946, it’s due!

When the star erupts it could be as bright as Gemma and the brightest stars in the Big Dipper.  While not bright like Sirius or even Venus, T Coronae’s brightness increases nearly 2,000 times.  The star may blaze for a week or so before it returns to its inconspicuous place near Epsilon Coronae Borealis (ε CrB).

Track Arcturus’ location throughout the spring, summer and autumn. T Coronae Borealis, the Blaze Star, is nearby so that when it flares you know where to look.

LATEST ARTICLES