Astronomy: Find the Summer Triangle in Dorset's dark skies

Silhouettes of father, daughter and astronomical telescope under starry skies

Scan Dorset's dark skies for the Summer Triangle - Credit: Getty Images/iStockphoto

Want to know how to locate the three constellations that make up the Summer Triangle, and when you can see the pearly swathes of glowing high-altitude noctilucent clouds? Bob Mizon, of Wessex Astronomical Society, reveals some sparkling summer treasure that can be seen in Dorset's dark skies 

At the Summer Solstice, on June 21, the Earth reaches aphelion, the furthest point from the Sun in its orbit. Furthest? The reason it’s so warm is that in the northern hemisphere we’re at maximum tilt towards the Sun. The glow of the Sun, now not far below the northern horizon, lingers all night at our latitude, and true darkness never really asserts itself.  

Star chart map showing the constellations for June 2022 in Dorset

June star chart - Credit: alanjefferis.com

Seek out the bright stars of summer. The Plough, in Ursa Major, the Great Bear, now sinks towards the northern horizon, with bright orange Arcturus (37 light years away), a dying ‘red’ giant, following it. To the south where the Milky Way falls to the horizon shines a red giant, Antares, Greek for ‘the Rival of Mars’ and 554 light years distant.  

Night skies and the Milky Way over St Catherine's Chapel in Abbotsbury in Dorset

The Milky Way over St Catherine's Chapel in Abbotsbury in Dorset - Credit: Getty Images/iStockphoto

The best-known feature of the June sky is the Summer Triangle, straddling the Milky Way. Its three bright blue-white stars are now climbing in the east: Vega (26 light years, in Lyra the Harp or Lyre), Deneb (1500 light years, tail star of Cygnus the Swan) and Altair (16 light years, Aquila’s ‘Eagle Star’).  

The summer triangle stars chart in the Northern Hemisphere

The Summer Triangle stars in the Northern Hemisphere - Credit: Getty Images/iStockphoto

A parade of planets now adorns the dawn sky. Early risers may see, from left to right, Mars, Jupiter and Saturn in the south-east, where brilliant Venus rises not long before the Sun. Look northwards at dusk for pearly swathes of glowing high-altitude noctilucent clouds, sometimes called polar mesospheric clouds. 

Click here for Bob's best star gazing spots in Dorset 

After sunset twilight with wispy noctilucent clouds

Noctilucent clouds can often be seen in summer after sunset - Credit: Getty Images/iStockphoto

Local Astronomy Talk & Walk  

June 7: Birth of the Solar System, talk by James Fradgley at the Wessex Astronomical Society, 7.30pm, Allendale Centre, Wimborne. wessex-astro.org.uk 

June 17: Solar System Walk in Weymouth Bay with Sara Harpley and John Macdonald. weymouthastronomy.co.uk