The Dancing Lady
An aurora at its best can be a spectacular display of pulsating lights and fluro colours in the night sky. Sometimes called Lady Aurora, or the “lady who dances", our aurora is the Aurora Australis, also called the Southern Lights, whereas in the northern hemisphere, the Northern Lights are the Aurora Borealis.
In April this year we were treated to an aurora event that was visible across the southern coastal region of Victoria. In particular, the night of Anzac Day eve put on a display that was witnessed and photographed by many. Photos taken in and around Sandy Point appeared on social media, such as this one taken at Cape Liptrap lighthouse by Tony Graziani.
The Southern Lights are mostly able to be seen further south, in Tasmania and Antarctica. However, when the aurora is very active, our location in Sandy Point makes us one of the best mainland locations to view it. This is due to our proximity to the most southerly point of mainland Australia (Wilson’s Prom), to our valued dark sky status, and our coastal view towards the south, unimpeded by light pollution.
Although most visible at the poles where they occur overhead, further away the aurora lights may be visible closer to the horizon. To see them with naked eyes is one of nature’s rare treats. If you are aurora chasing you need to be alert to favourable space weather conditions. You also need clear skies without cloud cover here on Earth, as well as dark skies without full moon or light pollution. Often the lights can be seen more vividly through a camera using long exposure on a tripod, and even using a phone camera on night setting.
An aurora occurs when increased sun activity, such as solar flares, creates solar wind that carries charged particles towards Earth. This is called a coronal mass ejection (CME). Our planet's magnetic field directs these particles north and south towards the poles where they collide with atoms in our atmosphere, creating the glowing colours - reds, greens and yellows from oxygen, blues, pinks and purples from nitrogen. This short video from the BOM gives a more detailed and scientific explanation. Ask the Bureau: What is an aurora? https://youtu.be/FpLd20_htF8
How do you know when to look to the night sky to see an aurora? The answer is "It’s not easy!". Astronomers are predicting that the sun will be going through the peak of its natural 11 year cycle of activity over the next two years, resulting in greater likelihood of aurora events. When attempting to predict an aurora event, you can check the geomagnetic data sets. For our location look for Kaus (not Kp) =>5, Bz <0, solar wind speed >400km/s. Detailed data and graphs can be found at the Australian Space Weather Forecasting Centre (ASWFC), Bureau of Meteorology. https://www.sws.bom.gov.au/Aurora. There are also apps such as the Glendale App from the UK, which now covers Australasia. https://aurora-alerts.uk/
Alternatively, you can get alerts from others who are constantly analysing the data for you.
Sign up to receive email alerts of possible auroras from ASWFC Aurora Alerts at http://listserver.ips.gov.au/mailman/listinfo/ips-aurora-alert.
Or go to the National Oceanic and Atmospheric Administration (US) and run the 30 - 90 minute forecast tool for the Southern Hemisphere. See sample results shown below. www.swpc.noaa.gov/products/aurora-30-minute-forecast
The coloured ‘donut’ indicates the area where the aurora is actually overhead - the range of visibility will extend beyond this depending on the intensity.
If you’re a Facebook user, groups such as Southern Hemisphere Aurora Group or Aurora Hunters Victoria will have a flurry of posts when conditions get exciting.
And be sure to follow us for any tip-offs on www.facebook.com/SandyPointCommunityGroup
Good luck with your aurora hunting! Whatever happens, remember to enjoy gazing at the star filled night sky, the Milky Way, the awesome sunset beyond Cape Liptrap, or the magnificent dawn over Wilson’s Prom - all hard to beat, with or without an aurora. All of these wonders are good reasons to value and retain our dark night sky in Sandy Point.
Please join us to support our advocacy for minimal and appropriate public lighting, and opposition to light pollution in Sandy Point. If you're not already a member of the Sandy Point Community Group, go to sandypoint.vic.au/membership to select either individual or family membership. A minimal annual membership fee ensures that we can continue to fight for the Sandy Point we all love.
By the editor, news@sandypoint.vic.au