What is an Aurora?

An aurora is a geomagnetic phenomenon that causes bright lights to appear above the Earth's polar regions.  The Sun is particularly active, especially during what is known as a solar maximum.  The Sun cycles approximately 11 years on average and maxima are characterized by an abundant number of sunspots.  I took the image below last Summer and it has a few sunspots.  We are currently heading into a solar minimum and thus the intensity and frequency of the aurora will be less.

Sun with Sunspots

The Sun expels ionized gas, electrons, protons and alpha particles.  These particles make it to the Earth 150 million kilometers away.  Since they are charged particles they get captured by the Earth's magnetic field and interact with matter present in our atmosphere.  An atom consists of a nucleus(protons and neutrons) surrounded by a cloud of electrons.  When energetic particles from the Sun interact with these atoms, electrons are excited to a higher energy state.  When the electrons drop back down to a lower energy state they emit photons at a specific wavelength.  This is what happens with neons signs.  Electricity excites the neon electrons to a higher energy level and when they drop back down you get the distinctive red/pink colour.

Oxygen in the upper atmosphere works much like the neon gas in a tube except on a larger scale.  Excited oxygen emits strongly around 558nm -- Green, while Nitrogen(lower in the atmosphere) causes deep blue and red colours.  Our eyes are poor receptors for colour vision at night.  This causes auroras to seem colourless when fairly dim.  It is only after we become adapted to the darkness and the intensity of the aurora increases can we see the colours.

What are the best ways to see the aurora from your location?

The first thing I would suggest is getting away from any urban setting.  Light pollution will significantly hinder any hope at seeing these geomagnetic lights.  The next thing would be to have a good computer program, social media source or mobile application that will crunch the large amount of data that goes into aurora forecasting.

We had a presentation in February 2017 on this very topic.  The consensus seemed the best mobile application would be "Aurorasaurus" by the New Mexico Consortium.  It is a free application that crowdsources space weather forecasting.  It uses realtime observations to create a map of where the aurora can be seen.  This is much better than other sites that tend to be overly liberal in their predictions that will cause you to go out to your dark site and see nothing.

http://www.aurorasaurus.org/

They also have a twitter account for live, up to date information.  Just navigate to @TweetAurora on your twitter account.

There is a great facebook group for Alberta observers known as "Alberta Aurora Chasers".  Monitoring the activity on this page will give you a great idea when and where a perfect aurora will appear near you.  If these members are getting out their equipment for a light show maybe its time for you to cruise out to a dark site where you can see the northern sky.

https://www.facebook.com/groups/AlbertaAuroraChasers/

I have also found that Space Weather Live provides great information.  Typically I get excited when the Bz value is below -10nT and the Bt is greater than 10nT.  A link to this site is provided below.

https://www.spaceweatherlive.com/

If you live in Calgary your best bet will be to go North, East or West to give yourself some great northern dark skies.  If you travel South you will have an ugly artificial dome of light emanating from Calgary.  However, that does not eliminate the possibility of seeing the aurora just South of Calgary as I took this image below from DeWinton.

Aurora in DeWinton

Good luck chasing the aurora!  Keep your eye on the forecast pages as they can changed minute to minute!