Saturday 6 October 2018 — ASTROPHOTOGRAPHY
It’s rare to have a clear night in the West of Ireland, but I was lucky while we were staying at my in-laws in Headford, County Galway. Rather than trying to take a quality astrophoto, I wanted to capture an impression of the rural sky and just how much we are missing in the south of England.
I put my DSLR on a tripod, set the ISO to 800, and set the lens to 24mm and wide open at f4. I spent a while checking the focus. I allowed the camera to autofocus, then switched to manual focus and used live view and zoom to make tiny adjustments until I was sure things were sharp. I then exposed for 20 seconds (This is a single shot). Zoomed in, even at 20 seconds, the stars are slightly smeared by their apparent movement across the sky (actually a result of the earth’s rotation) and very slightly smeared by vibration (it was quite a windy night) but at a reasonable scale I think they are acceptably sharp.
This view was roughly eastwards. The town of Tuam is about 15km (10 miles) in that direction, with a couple of tiny villages (with very little lighting) in between. Even so, the reflection of sodium streetlights on the wisps of cloud are obvious, The hedge is comparatively brightly lit by the streetlights behind me (and the house) on the road outside. I have been visiting that house for many years, and the light pollution from Tuam is visible to the naked eye now, when it was not when I first saw the night sky there. As Ireland develops (a good thing) its natural heritage is being polluted and is ebbing away, as it has in so much of Europe. Light pollution is not as disgusting as chemical, or as obvious as loud noise, but it is just as much a stain that people put on the environment that supports us. Light pollution limits our experiences, as well as damaging wildlife and people. There are some good people in Ireland fighting for dark skies Mayo Dark Skies and I hope they prosper. I can understand people needing light at night, and needing security, but it needs to be done with respect and efficiency, and certainly not through glaring floodlights that blight everyone else.
We have much, much bigger problems in England. When I took this photo, the Milky Way was arching overhead, so bright it seemed solid, with detailed texture and structure, almost too much too see. I couldn’t capture it on camera well enough to share, but I will never forget the sense of awe it gave me. I am pleased to be able to see the Milky Way routinely where I live now (at my last house that was very rare), but it is a very pale shadow of how it looked in the West of Ireland.
The small group of stars just above the hedge is the Pleiades, or seven sisters, a star cluster. Above and slightly to the left of them is the contellation of Perseus. At the top (about a third of the way in from the right)is a slightly yellow smudge or blurry “star”. This is the Andromeda Galaxy, which was clearly visible as a brightish smudge to my naked eye. It is about 2 Million Light Years away (or roughly 2 followed by 19 noughts miles!) The light to make that smudge has been travelling for 2 million years to reach our eyes. The field of view is roughly like this: