Deep sky challenge
With the Big Dipper laying flat above the western horizon at sunset, June nights are perfect for exploring the hidden treasures of Ursa Major
June nights are perfect for exploring the hidden treasures of Ursa Major
Think of the constellation of Ursa Major and you probably think of the seven bright naked-eye stars that make up the famous asterism ‘the Big Dipper’ – or ‘the Plough’, or whatever you want to call it – including the best-known double star in the sky, Mizar, and the twin ‘pointers’ that point the way to Polaris, the Pole Star, in neighbouring Ursa Minor. But this much-loved constellation – stretched out across the western horizon as darkness falls on these early summer nights – has a lot more to offer.
Lurking inside the boundaries of Ursa Major are many deep-sky objects unfamiliar to – and unobserved by – many telescope owners. There are plenty of galaxies for observers who like the challenge of hunting down those faint, distant star cities, and some brighter nebulae within our own Milky Way galaxy too.
The close pair of M81 and M82 is much loved by owners of small telescopes, but only larger instruments will show detail in the arms and centres of these far-off galaxies. The Owl Nebula, or M97, is very popular with observers of planetary nebulae – the glowing shells of dying stars – because it really does resemble the face of a wise old owl when seen through a high-power eyepiece in a large telescope.
“The close pair of M81 and M82 is much loved by owners of small telescopes, but only larger instruments will show detail in
the arms and centres of these far-off galaxies”
1
Messier 108
This barred-spiral galaxy is 45 million light years away. Shining at magnitude +10, it is visible as a featureless elongated smudge in 6” telescopes. Larger apertures will reveal some subtle mottling.
2
Messier 109
Magnitude +9.7, this barred-spiral galaxy is merely a small, pear-shaped blur in small telescopes. Instruments of six inches and larger will show the subtle glow of its spiral arms.
3
The Owl Nebula (Messier 97)
Faint and with a low surface brightness, you will need at least a medium-aperture telescope to see the two dark ‘eyes’ of this magnitude +9.8 planetary nebula.
4
Messier’s Mistake (Messier 40)
This object is a strange curiosity in Messier’s catalogue because it is not a galaxy, nebula or cluster but a close pair of stars. It is just an optical ‘line-of-sight’ double rather than a genuine binary.
5
Bode’s Galaxy (Messier 81)
At magnitude +6.8 this spiral galaxy is bright enough to be visible in binoculars as a tiny smudge, but it takes telescopes of six inches and up to show its beautiful spiral arms and bright core.
6
Cigar Galaxy (Messier 82)
Just over half a degree away from M81, M82, the ‘Cigar Galaxy’, is much smaller and fainter than its more obvious neighbour. A large telescope will reveal light and dark patches along it.