A Tutorial on Aurora BorealisForecasting, now-casting, and photography
Last update: October 25, 2011
I frequently get asked how I know when auroras will be visible, and people often ask me to call them when I am seeing them. This last display I was overwhelmed with the amount of people calling/wanting me to call them while I am trying to take photographs. In most circumstances this wouldn't be a big deal, except that severe aurora storms don't last every long. Getting correctly exposed, properly leveled horizon, and focused pictures while trying to call people doesn't tend to produce good results. So I decided to make this tutorial page to help people understand how to know when there will be auroras.
One must understand is that based on your latitude, auroras can be either extremely rare or common. Generally north of 50 degrees north, auroras/Northern lights are commonplace. South of there however, it takes a bit of luck and patience to observe them. A lot of patience. I can't tell you how many times I've been out waiting and hoping they would appear when (as far as I knew) conditions were favorable for them and come home empty handed. Dozens of nights I've spent countless hours waiting, all for nothing.
How do I know when auroras will be visible?
The first thing to watch for is an active sun with lots of sunspots. We are coming into a solar maximum (nearing the peak of sun activity in this solar cycle) which is forecast to peak in 2013. This means that aurora displays should be more frequent in the next few years. If there plenty of sunspots, One would want to monitor the X-ray solar flare charts from the Space Weather Prediction Center (SWPC). Here is an example of an active chart with multiple X flares, if these were directed toward earth (the sunspot was near the center of the sun/earth facing), there will likely be auroras.
Some of you may be familiar with Spaceweather.com. This website is a great resource to find forecast information, however DO NOT be fooled into buying their "phone alert" service. Auroras come and go in a flash, by the time the author of the website knows they are occurring and activates the system, the display is very likely to be over. Spaceweather is good to monitor solar flares and CME impacts, this is what will cause geomagnetic storms, and aurora. I use this chart a lot to see up to date plots for solar flares. Typically one would want at least an M flare with a large ejection visible on the videos posted by spaceweather. EXAMPLE. Once you have an idea what night/time the flare or CME will hit, then it is time to start now-casting.
If you don't book mark any other link I post on this page, make sure you bookmark this one. This is the page I use the most to monitor aurora potential on a given night.
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