The aurora over the Firth of Clyde (credit: David Palmar Photography www.photoscot.co.uk)
Aurora alert!
According to a popular internet search engine, the phrase ‘aurora borealis’ was among the top one hundred searched-for terms in the UK in 2005. The aurora really has to be seen to be appreciated. Neither still or moving images can do it true justice. Judging by the number of aurora-watching holidays advertised in the travel sections of the Sunday papers, this complex and beautiful natural wonder captivates those with an adventurous spirit. But do you really have to travel to the Arctic circle to witness the aurora borealis first-hand, or can it be seen from the UK? If you are lucky, then yes it can.
Typically, aurorae are observed within crown-like ovals that surround the northern and southern geomagnetic poles. During intervals of high geomagnetic activity the ovals expand equatorward, while quiescent periods cause them to shrink poleward. Consequently, the likelihood of observing an aurora at mid-latitudes varies widely, depending on the current state of the 11-year solar cycle. But we can expect to see visible aurora over the UK a couple of times per year, albeit with a preference toward the northernmost parts of the country.
The AuroraWatch programme is a real-time service that alerts subscribers when geomagnetic conditions are likely to produce an aurora over the UK. A red alert indicates that geomagnetic conditions are sufficiently disturbed that your chances of seeing an aurora are good, while an amber alert corresponds to moderate activity and a lower likelihood of an aurora.
An alert takes the form of a short email with the status given in the subject line. You can take advantage of the free email forwarding services offered by most mobile phone networks, and have alerts forwarded as SMS text messages directly to your mobile phone. You can opt for both amber and red alerts, or red alerts only.
The AuroraWatch programme has been highly successful. In October 2005, it recorded its 20,000th subscriber. Of course, not every alert results in a spectacular auroral display and where you live can dramatically improve or reduced the chances of a successful night’s aurora-spotting. Bright streetlights from large towns or cities will overpower faint aurora. Those of you who live in the rural north of the UK are more likely to see an auroral display than those inside the M25!
As we are currently, approaching a minimum in the 11-year cycle of solar activity it is expected that auroral displays over the UK will be at their most infrequent. Nevertheless, based upon photographs taken by AuroraWatch subscribers, it is known that clear aurorae were observed on at least two nights in 2005. The AuroraWatch gallery is full of images taken by AuroraWatch subscribers from as far north as the Shetland Isles to the south coast of England. All it takes is a fine night and a little luck . . .
AuroraWatch is part of a larger project, called SAMNET: The sub-auroral magnetometer network. See the SAMNET article on this website. Plus, more information can be found at the AuroraWatch website http://aurorawatch.lancs.ac.uk/
