These are some I took last night in Northern Tas. They are a bit grainy, due to the settings on my camera I'd suspect. As these are the very first ones ever I have taken of an Aurora, any hints or tips to make them look clean and not grainy?
Pentax KM, ISO 3200 and 1600, 30 sec and 20 sec, F3.5.
Unfortunately it's a matter of the nature of the beast, just try lowering your iso to 400 - 800 and increase the exposure to compensate. You will obviously increase the star trailing as well but if you're mainly after the Aurora and not so much the shape of the stars, then that's the best you can do. Some cameras handle noise better than others. Despite the noise you've managed to capture the event nicely, I like your middle shot the best. Good for getting out there in the cold and giving it a go.
You could always try a slight Gaussian Blur or De speckle in Photoshop if you have it. That can help at reducing noise, at the sacrifice of losing some detail though. You could also try taking a few dark frames and subtract them from your shots. Good luck.
