Aurora of May 2024

The Sun’s behaviour around the time of the Aurora seen on Earth

All images by GAS members, solar images in white and Hydrogen Alpha light

Click on an image to enlarge it.

The Auroral effects of the geomagnetic storm caused by Sunspot group AR3664 & AR3668

Photographing The Aurora

The easiest option is to use your mobile phone. Some newer models have a night mode that enables a longer exposure eg 3 seconds if the flash is turned off. They often allow for longer exposure if mounted on a tripod.

When taking a long exposure photo, you need to keep as still as possible. If there is a solid surface to lean or rest on, this can help, I have even seen people take off their shoes and place them on a solid surface and place the phone in there as a temporary tripod. However, tucking your arms in and against your chest can help with this too.

If you have a proper camera, then a widefield timelapse could be done as well as some long exposure images. However, don’t lose time enjoying the experience to set up a proper camera if you are getting decent pictures or naked eye experiences on your phone. You may miss the entire event by getting distracted.

Preparation Is Key

The key thing to do here so you don’t miss a display because you are setting up is, make sure you know your phone and camera settings in advance. Practice taking photos in the dark, with long exposures and all the settings.

Also, if the forecast is looking favourable, prepare everything in advance. If you are just going outside, attach your camera to your tripod with all the settings ready to go.

Have your keys, phone and anything else you need in one place ready to go. If you are expecting to wake up in the middle of the night to go out, then have your clothes and red light torch ready to go too.

If you are driving somewhere, then pack your car with everything you need (including snacks, supplies, camping chairs etc) so you can just get in and drive.

You can see some photos taken by members of GAS throughout this post.

Auroral Colours

The colours of the aurora are due to the chemistry and the altitude. The atmosphere is made up of approximately 78% nitrogen, 21% oxygen and 1% other gasses.

The most common aurora we see is the green aurora which is oxygen at altitudes of 60 to 190 miles or 100 to 300 kilometres (according to the Canadian Space Agency). Green is also the colour that the human eye, and a standard DSLR is most sensitive to picking up.

Red is also caused by oxygen at 180 to 250 miles or 300 to 400 km.

There is also a red caused by nitrogen above 96 km or 60 miles, however, usually the nitrogen below that is which looks blue is excited too so it looks more purple and blue.

Other colours such as orange, yellow and white are due to multiple layers of these in the line we are looking at through the atmosphere combining to create other colours.

Auroral Shapes

There are a number of shapes you might see, starting with diffuse, which is just a sort of cloud of pale colour with no defining shapes to veils or curtains, arcs, bands, rays, and all sorts of wonderful shapes.

Sometimes these seem to dance and change a lot too. It is thought that pulsing aurora that can pulse very slowly, fading in and out of view or more clearly pulsing is caused by waves of charged particles scattering electrons into the atmosphere whereas the more clearly defined shapes are thought to be caused by electrons being accelerated into the atmosphere when Earth’s magnetic field, stretched out by the solar wind, reconfigures itself.