I’m good at finding my way around in the dark; I had training as a child. In our house, we weren’t allowed to put the lights on if Dad was observing with his home-built telescope. My father’s main criterion when choosing a house was the location… of streetlights. For the amateur astronomer there are two main frustrations: clouds and light pollution. The UK now has several dark sky parks but generally, if you can get away from the cities or motorways, you’ll see much more.
We’re used to relying on electric light to guide us but if you wait 30 minutes, you can find your way around in ‘pitch black’. Your eyes adapt: within the first minute your pupils widen to let in more light, within 10 minutes your ‘cone cells’ will adapt and over the next 30 minutes your ‘rod cells’ in your retina will have come into their own, meaning you can guide yourself by starlight. Don’t look at your phone or car headlights or you’ll have to start again. Now you’re ready to follow Professor Stephen Hawking’s advice: look up at the stars, not down at your feet.
Welcome to shooting stars
The Perseid meteor shower happens every August. 2018 promises to be one of the best displays of shooting stars we’ve seen in a while. This is because the moon won’t be shining, making the sky darker. On the night of 12 August, check the weather forecast to find a cloud-free area, grab a blanket and head to the darkest spot. Lie back and watch a beautiful display of around 60 meteors an hour. If you wear glasses or contact lenses for distance, be sure to have them on; you won’t need binoculars or a telescope.
What else can I see?
While you’re there, look for the smoky strip of the Milky Way, which spans the celestial hemisphere overhead. You’re gazing into the centre of our galaxy from our position at the unfashionable end of the western spiral arm.1 Our galaxy is a flat disc and you’re observing it side-on. The bright white star nearly overhead is called Vega.
The small cluster of stars in the northeast is the Pleiades (or ‘Seven Sisters’). If you can make out six or more separate stars with the naked eye, you’re doing well but with binoculars you’ll see there are many more in the cluster.
What’s that shiny thing?
If it’s firework-fast, bright white with a long tail, trailing across the sky, it’s a meteor. If it’s bright, flashing and moving slowly it’s an aeroplane.
If it’s moving a bit quicker, bright white and not flashing, it’s probably the international space station.
Anything else you can assume is alien technology.
1. Adams D. The hitchhiker's guide to the galaxy. New York: Harmony Books; 1979.
Ceri Smith-Jaynes is OT’s Multimedia Clinical Editor and is an optometrist in independent practice in Lancashire