19-07-2025
Finding the summer triangle in the night sky this week
Looking at Vega whilst facing east, sweep a short distance down and to the left, and you'll find Deneb. Sweeping down and to the right from Deneb, Altair, can be found at a greater distance situated above the southeastern horizon. Together, these three bright stars form the 'Summer Triangle'.
As featured in last week's article, astronomers now believe that 3I/Atlas, the 12 mile-wide object that recently entered our solar system, is literally a wandering galactic relic that is probably billions of years old. Discovered by the Asteroid Terrestrial-impact Last Alert System, (ATLAS), telescope in Chile, 3I/Atlas is gathering a similar amount of attention as the large cigar-shaped object Oumuamua, (pronounced oh MOO-uh MOO-uh), drew when it passed through our neck of the woods in 2017.
3I/Atlas is currently speeding through our solar system at 150,000mph, scheduled to Mars in October at a distance of 18 million miles from the red planet, then passing Earth at a distance of 150 million miles in December.
This intriguing object is thought to be in the order of seven billion years old, older than our Sun, estimated to have formed 4.6 billion years ago.
Measuring larger than the asteroid that brought the curtain down on the reign of the dinosaurs, 3I/Atlas heralds from a completely different region of the Milky Way, when compared to the previous two visitors, Oumuamua, and 2I/Borisov, the latter of which was discovered in August 2019.
Recently, a very rare event took place in the southern hemisphere whereby not one, but two stars went nova, giving observers the chance to see two 'new stars' shining brightly at night. In northern hemisphere skies, the skies we observe, (and not to be outdone), we may well have our own nova to look forward to.
A nova and a supernova derive from the same stable but arise from different causes involving stars in different phases of their lives, but needless to say a supernova is a major outburst with a nova less so. The latter applies to a star named T Corona Borealis which every 80 years dims slightly before erupting, and should become visible to the naked eye.
T Corona Borealis is situated in a small constellation named Corona Borealis, not far from the bright star Vega. Whilst noted in Greek mythology, Corona Borealis also has a place in Welsh mythology, being referred to as Caer Arianrhod, 'the Castle of the Silver Circle,' the heavenly residence of Lady Arianrhod, the 'Silver Wheel Goddess of Wales'
Lasting occurring in 1946, T Corona Borealis dimmed in March 2023 as a precursor to the nova occurring, and if the outburst follows the same pattern, we could well see a nova in our skies.
Venus continues to 'shine' brightly in the skies before dawn and on mornings of Monday, July 21, and Tuesday, July 22, the crescent Moon makes for a lovely pairing.
Send your astrophotography pictures to: thenightsky@
