Aurora

An Eccentric Anomaly: Ed Davies's Blog

Last night (2017-11-07 Tue) there was the best aurora display I've seen.

There were various email alerts and tweets earlier in the evening but when I looked out around 20:00 there was nothing to see. Just before 10:30 I looked out of the skylight in the spare bedroom and thought I could see a green glow so I got my camera ready then turned off lights to dark adapt a bit while adding outdoor clothes by red LED head torch.

The adaption was probably rather academic as there was such bright Moonlight. I hid from it round the back of the house (north west side) and immediately saw the brightest aurora I've ever seen with marked vertical banding and a very bright band directly to the north. For the first few minutes there was visible movement in the bands slightly to the east of north.

The only previous time I've seen movement was a few years ago (2014-02-23 Sun) when I saw a solid green arc with a sharp top edge which pulsed slowly.

I took some photos. They're rubbish but at least I know why. Firstly, they were hand held braced against a rough and slippery stone wall. Secondly, I had the camera on manual focus. It can actually focus well “beyond” infinity; I thought I had it wound back enough to compensate but it really needed to go back a bit further.

All images were at around the shortest focal length my kit lens can do (around 18 mm) and ISO 3200. As usual, click on images for a somewhat bigger version. The first few were at 1/2 second exposure giving results pretty much like naked eye:

Four second exposure showing a bit more detail than could be seen by eye:

Looking further round towards the west with red which definitely wasn't naked-eye visible:

Eight second exposure looking north showing the brighter beam:

I took a few more pictures but they don't add much. The whole display faded quite rapidly disappearing more-or-less completely within about 10 minutes of me going outside so I went round to the front of the house to have my eyeballs blasted by the Moon and to play with focusing a bit. First without changes, Moon, Orion and lots of engineering on the sea with the decommissioning of the Beatrice oil field and the construction of the wind farm.

Much better focus but a bit of a wobble:

Somewhat better apart from the tilt from resting on a dry-stone wall:

Hmmm, Argos have a reasonably cheap tripod which has mostly good reviews but maybe I'll wait until next week's Caithness Astronomy Group meeting to pick people's brains.