Monday 16 May 2005
Aurora Australis
We've had clear skies and low winds for almost a week now, giving us some great views of the Aurora Australis - the southern lights. First, the science bit:
Aurora are caused by high energy particles from the Sun hitting atoms and molecules in our atmosphere (such as nitrogen or oxygen). They absorb the energy of the particles and re-emit it as light, creating bands of fast-moving coloured light that can stretch across the whole sky. The particles from the Sun are charged so they follow the lines of the Earth's magnetic field, creating ovals of aurora around the north and south poles when the Sun is active. Auroras are one of the things we study here at Halley - in fact this site was chosen specifically for that reason, so we tend to get some spectacular displays in the winter months.
Taking good photos of aurora is extremely difficult, because they can move very quickly and tend to be too faint to show up clearly. My camera isn't really up to the job as you need long exposures and very low noise levels. As well as a good camera you need a lot of patience as the brightest and most spectacular features often appear in an instant and vanish just as quickly so you need to spend a lot of time out in the cold waiting for that perfect shot.
While I've been here, Jeff has become the official aurora photographer for the whole base - no one else can compete with his pictures so many of us have just given up trying! He has kindly let me put some of his pictures in an aurora gallery.
Posted by simon at 1:34 PM | Feedback (14)