Gaze on galaxies

A version of this article appears in Scilly Now & Then magazine's March/April 2020 edition.

Spring is on its way! Clouds begone! You don’t need to have a brain the size of Stephen Hawking’s to know that clouds plus stargazing equals zero. I won’t go on (again) about the weather; a let-up will be welcome.

One rare but utterly lovely clear night last month, a group of us ventured up to the observatory, as naturally we are wont to do when the opportunity arises. Partly this was administrative: I’d had word that our smaller telescope was playing up and wouldn’t point where it was supposed to. If a go-to telescope doesn’t go-to where it’s supposed to go to, it’s a) a problem and b) annoying. You can’t easily solve alignment issues during the daytime when you’d like to, nor on a cloudy night as you need to be able to actually see to verify the celestial objects you’re supposed to be looking at. None of us that night wanted to tinker, we wanted to be wowed.  And gladly there ends the non-anecdote, as said telescope was fully functional. Nothing is ever perfect in our corner of amateur astronomy (we're all learning rapidly), but workable is a huge relief. In any case, after being underwhelmed by bright Venus (it’s so bright that, even with a filter, magnification doesn’t add much), we set our sights on some lovely deep sky objects, including our nearest galaxy, Andromeda.

A galaxy is - to cut a long story short - a big old group of stars bound together by gravity. Think of them as cosmic super-factories, creating on a grand scale. Ours is the Milky Way, comprising some 250 billion stars, our Sun one of the distinctly average thereof. But the Milky Way is only the second-largest in a cluster of some 50 other galaxies known as the Local Group. I say group, we’re pretty far apart. Andromeda’s the nearest to us and that’s a tidy 2.5 million light years away from Earth. (That would be approximately 23,651,826,000,000,000,000 km... to ground you, a walk around the entire coast path on St Martin's comes in at less than 10km.) The whole of the Local Group spans about 10 million light years across (don't make me write it). There’s nothing like astronomy to put you in your place!

There’s a particularly interesting patch of sky on view right now, known as the Realm of Galaxies, less fantastically as the Coma/Virgo Supercluster. It’s the galactic heartland of the Local Group, and now is a very good time to go on that deep sky tour you’ve always fancied. Sadly you won’t see galaxies with the naked eye – you’ll need a decent-sized telescope.

Located between constellations Virgo and Coma Berenices, you’ll find this richly populated region in the Eastern sky after 10pm. Locate Spica, Virgo’s brightest and distinctly blue-hued; to its left find Bootes’ brightest, orangey Arcturus (incidentally an ageing 7.1bn old red supergiant). Join a line between the two and then imagine a point forming the tip of an equilateral triangle above – this points to the area of the Realm of Galaxies. If you don’t have a telescope, you’ll just have to make do with imagining the many worlds out there. Still: humbling.

If you’d like to join us (and our telescopes), the observatory on St Martin’s is open again from April. Regular openings are Tuesday nights, 8-10pm, and Friday afternoons, 2-4pm. We recommend booking in advance so email [email protected] if you’d like to come along.