Hunting for Aurora
All night long...
Aurora on site
Northern lights, or aurora borealis, can be seen easily from the garden and lake directly in front of our cabins, as in the pictures here. Aurora start in autumn and continue on and off throughout winter until spring, being stronger around the equinoxes. Since we are located in the middle of the wilderness, by a large open space and far from city light pollution, the views are incredible.
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The aurora often form arcs from horizon to horizon and sometimes the arcs begin to twist and sway like curtains in the wind, occasionally expanding to fill the whole sky. The aurora can also take on a more cloud-like appearance, but if you are lucky, they can be seen moving fast and shining very brightly. They are more common around midnight, but can actually appear at any time during the evening and will fade away before sunrise. The picture below shows all of our buildings and the aurora, photographed from our lake with an iphone - the cabin lights are obviously not strong enough to obstruct the light from the aurora!
Aurora Tours
The aurora come and go during the night. However, they can only be seen on clear nights and even then, they might only last for a few minutes, so when the forecast is good, it's best to be outside as soon as it gets dark. Since the aurora can be seen from our garden on clear nights, it's not necessary to book an aurora tour elsewhere. But, if it's cloudy, we have a guide who can take you to places where there are no clouds (more info at bottom of page). If you have a car, you can try to find those places yourselves.
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There are many apps with aurora activity forecasts that are free to download. The apps use data from satellites, and since they use a real-time feed, they can give accurate predictions for the next 15-60 minutes. Look further down the page for help in reading app forecasts.
What are Aurora?
The aurora are determined by the activity on the sun. Space is filled with a constant stream of plasma from the sun called the solar wind. The magnetic field surrounding our planet makes sure we are protected from the solar wind, which carries charged particles from the sun called electrons. These accelerate up to 20,000 km/second along the Earth's magnectic field lines towards the north and south poles. The electrons react with our atmosphere where the magnetic field lines converge and curve down towards the magnetic poles. Here the electrons collide with our oxygen and nitrogen atoms at altitudes from 1000 kilometres down to 100 kilometres. When this happens, the atoms temporarily get a boost of energy. This energy causes them to release photons, which we see as light. Energised oxygen atoms produce green and red light, while nitrogen atoms produce blue and purple light, thus making the aurora that we see in the night sky.
Aurora Forecast Apps
Here's some things you need to look for with aurora forecasts:
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First, the KP index, which is a measure of magnetic activity, where 1 = very little magnetic activity, 5 = high activity and signifies a minor magnetic storm and 9 = a very powerful magnetic storm. Our coordinates are 66°53’53”N and 26°12’0”E so we are in the KP 3 zone, which means aurora can be see overhead and in the northern sky when the KP index is 3 or over. Since a higher KP also signifies a wider auroral oval, maxing at around midnight, it means there's a better chance of seeing aurora further south too.
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Secondly, the speed of the solar wind, which is measured in kilometers per second (km/s) and is normally around 300-500 km/s. However, when there is a hole on the sun's surface, called a coronal hole, the solar wind escapes at a higher speed. The higher the speed, the harder the particles hit the Earth’s magnetosphere, increasing the chances of strong and colourful aurora. Speeds can reach up to 1000 km/s.
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Thirdly, the particle density, which indicates the amount of particles coming from the sun. This value is usually given in cubic centimeters (p/cc or p/cm³). When there's a solar flare or an explosion on the sun, called a coronal mass ejection (CME), large amounts of charged particles are expelled into space and are carried along in a solar wind shock wave. The more particles in the solar wind, the more chances we get for an auroral display, as more particles collide with Earth’s magnetosphere. Again, the higher the better, so 20 is good and 40 is high, and a value of 100 is extremely high.
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Finally, both the Bz and the Bt values are important measures for auroral activity. During periods of minimum solar activity, the sun only exhibits a dipole magnetic field similar to that of our planet. However, when the sun is more active, additional magnetic fields arch between sunspots on the east-west axis. The state of these magnetic fields (the strength and polarity of the magnetism) is locked into the solar wind as it sets off into our solar system as the interplanetary magnetic field (IMF). The Bz value gives the north-south direction of the IMF: a negative Bz value, such as -10 nano-Tesla (n-T), indicates that solar particles will mostly impact the Earth's magnetosphere in northern latitudes, while a positive value indicates that they are more likely to occur around the south pole. The Bt value, on the other hand, gives the strength of the IMF: the stronger the IMF, the greater the magnetism, so more aurora! A Bt value of at least 10 nT indicates a mild goemagnetic storm, while 30 nT is a very intense storm.
For more science and an aurora tutorial, go to the space weather prediction centre at NOAA
