** UPDATE: April 15 – Sadly this weekend’s aurora was a fizzer. The CME hit at around 9:00 Sunday morning and unfortunately wasn’t anywhere near as strong as it might have been. **
Attention aurora australis hunters – there was a fairly major solar flare on the sun yesterday which produced a large coronal mass ejection which is due to hit the earth sometime this weekend. The results could be quite impressive as this flare occurred in the centre of the side of the sun facing the earth. This flare was even bigger than the one that caused the spectacular aurora display of March 17 2013.
A lot of people have asked me how and where to see the aurora australis, or how to find out in advance when one is likely to occur. The answer lies in being aware of these solar flare eruptions on the sun. No one can predict in advance exactly when a solar flare will occur, but once it happens we then have a nice 2-3 day window to expect the aurora. Yesterday’s explosion was classed as an “M6″ solar flare. Solar flares are categorised as B, C, M and X with B being very weak and X extremely strong. All flares are classed in one of these categories along with a number from 1-9, with 1 obviously weakest and 9 strongest. So an M6 flare is in fact quite a large flare.
The next condition that needs to be met is that the flare must cause a “Coronal Mass Ejection” – or CME. This is in fact the most essential part as it is the CME interacting with the earth’s magnetosphere that is what we are witnessing when we see an aurora.
When choosing a site to view from the most important thing is a clear southern horizon/sky away from the light pollution of big cities. The aurora doesn’t look as colourful to the naked eye as what the camera captures but it is still a mesmerising experience as the aurora shimmers and dances across the sky, like a silent fireworks display.
Some of the websites I monitor are:
Space Weather – great info on all goings on in the night sky, not just aurora
IPS – The Australian Government space weather page. They have an aurora alert email list you can join
Geophysical Institute, Alaska – this page has an aurora visibility predictor for the southern hemisphere as well as the northern hemisphere