It’s summer, and with August comes darkness just that bit earlier than in midsummer. And with the holiday period upon us, there’s more opportunity for stargazing in the evening.
What’s there to see in the August skies? It’s hard to miss the planet Jupiter, a really bright object way down in the south-west at the moment. Look to its left and you’ll see another bright object, which is Saturn. Even if you don’t have a telescope of your own, keep a lookout for one of those coin-in-the-slot seaside telescopes which with luck will tilt up high enough to let you see a bit of detail on the two planets. They usually magnify about 20 times, which is all you need to start seeing them as actual planets rather than dots.
In the case of Jupiter, you’ll see its disc quite easily. Notice that it’s slightly flattened. rather than circular – a result of its rapid rotation. It spins in about 10 hours, and as it’s a giant planet made of gas (it’s around 11 times the Earth’s diameter) the forces on its outer layers cause it to bulge around the equator. After a few pub dinners you may also bulge around your equator, but that’s another story.
Even with binoculars you can see Jupiter’s four brightest moons, on either side of it – though all four might not be visible when you look, as one or two might be behind or in front of the planet. Look again another night and you’ll see that they are in different positions as they orbit Jupiter. Their names are Io, Europa, Ganymede and Callisto. All but Europa are larger than our own Moon.
And if you’ve never seen Saturn through a telescope before, you may be amazed that even through a seaside telescope you should be able to see its famous rings. It’s a glorious sight, even at low magnification. This year in particular it’s very low in the sky, so our rippling atmosphere makes a mess of the view at high magnification, but with a small telescope the image will just shimmer a bit.
If you can get away from the streetlights, look overhead and you may be able to see the Milky Way quite clearly. It looks so bright in a dark sky that you wonder how you missed it before – but light pollution drowns it out for most of the UK’s population these days. The Milky Way is actually the light from billions of stars, each too faint and distant to be seen individually, which make up the galaxy we live in. If you can see it well you’ll see the dark rift along it, which is the result of dust and gas between the stars.
The bright star virtually overhead is Vega, in the small constellation of Lyra, the Lyre. Some way to its left is another bright star, Deneb, which is at the top of what people call the Northern Cross, but which is actually part of Cygnus, the Swan. And in mid sky, making a big triangle with these two, is Altair, which has a fainter star on either side of it. If you want to identify more stars, and don’t have one of those app thingies on your phone, use our Sky This Month map. Click on the time and location box at its top right to change these details.
The SPA is all about stargazing, so don’t let this be your only venture into the night skies for the year. Get to know the stars, and join the fun!