Aurora Photo's from Tekapo

Tekapo will get a handful of auroras every year, I keep getting asked what season can we see them sorry to say as I have noticed we don't have an aurora season they just happen any time. For an aurora to be seen in Tekapo it needs to be very active. 2005 we were very lucky to see 2 very nice aurora displays so far this year I have only seen 1 very small aurora, also I might add because of the time exposure cameras catch a more intense colour and light than we would see with our own eye. If you would like to see what the aurora is doing now please check
www.sec.noaa.gov/pmap/
It also needs to be a clear cloudsless night that has less than a half moon, you can check our current weather on
http://www.metvuw.com/satellite/
Basically you need to be in the right place at the right time.

Above Aurora photos from Sunday 15th May 2005, over looking firstly my house then from the Church of the Good Shepherd then from Lilybank Road over looking Lake Tekapo with Mt John and Tekapo Village

Below Photos from August 25th 2005, although this was a very intense aurora it clouded over in half an hour and was no longer visable. But this is my favourite aurora because of its intense colour and the way it passed along the sky from east to west

Aurora Australis

This is the name of the southern lights often seen at the lower latitudes of New Zealand on a clear dark night. The phenomenon begins at the sun where a particularly large coronal outburst creates a strong stream of charged particles known as the solar wind. The solar wind interacts with the Earth's magnetic field lines at the altitude called the magnetopause and the charged positive and negative charges are then associated with the Earth's magnetic field, creating a large charged electric field concentrated at the poles. In the southern hemisphere the field lines are streaming out of the Southpole which is like a north pole of a magnet. Current flows between these electrical polarities, through the ionosphere, across the polar region and back. The streams of electrons which are the negatively charged particles are flowing - spiraling, along the magnetic field lines and intercepting the oxygen and nitrogen atoms in the upper atmosphere. These excite the oxygen and nitrogen atoms causing them to fluoresce, just as they do in a conventional neon fluorescent light tube. The only difference is the excited oxygen atoms emit a greenish white light, and the nitrogen molecules which are excited by more energetic electrons are made to emit the red to pinkish colours. Ionised nitrogen gives off a blue violet light. The light emission or fluorescence from atoms is caused when electromagnetic energy strikes an atom raising the electron orbital level to a set, higher energy level, which may then collapse back again emitting a photon of light of a particular wavelength. This determines its colour.
(Written by Peter Cattell 31 May 2005)

How to take Aurora Photo

Taking a photo of an aurora is quite easy if you have the right equipment, you will need a camera that has manual settings or a night shot mode and a tripod or something to rest the camera on while you take the photo. It does not matter if you use film or digital, but digital is good because you can check results straight away. If using film you will need some that is very senitive (ISO 800 or higher) this will make the photo a bit grainy but you need to capture as much light as possible. For digital camera set the ISO to the highest setting. If using a SLR / DSLR set the lens to manual focus and then set that to just before infinity and as wide as possible (anything below 35m) Set the shutter speed to 30 seconds (or as long as you can with your camera) and set the aperture to as wide (open) as possible f/1.4 - f/3 anything over f/4 will make the photo a bit dark but you can compensate by making the shutter speed longer. Once you have done all this it is just a case of placing the camera on a tripod, pointing it in the right direction and pressing the shutter release.