The best time for viewing and capturing the Aurora Borealis is around midnight.  Typical hours are 10:00 PM to 2:00 AM but can extend another hour either side.What do you look for:  Keep your eye out an "Auroral" break up. It is the quick change over from plain formations to formations that look like rays.  Colored rays swirling across the sky will typically follow this.  This activity starts near the horizon to the east in the earlier hours and south in the peak hours. Look for Aurora predictions of medium to large.  For a medium or moderate Aurora the activity may last under a minute whereas a large Aurora may last a few minutes or more.

Camera Preparation

LENS: You will need your wide-angle lens 14mm to a maximum of 50 mm, f/2.8 or faster is preferable.  PLEASE REMOVE ALL FILTERS FROM THE FRONT OF YOUR LENS.  No UV filters and no Skylight filters.  These will create reflections and show up as concentric circles on your image. A crop factor APSC camera will give you a 35 mm equivalent of 21 to 22 mm when you use a 14mm lens and 75 to 80 mm when using a 50mm lens.  You will need to stay at 50 or below equivalence.

FOCUS: Prepare your camera lens combination during daylight hours.  Set your focus reading by focusing an object at infinity.  Do not rely on the infinity mark of your lens – there are too many variables.  Use masking tape or other plumbing tape to mark the focus point.  You can even use the tape to hold the focus in position.  Set the lens to manual focus and do not attempt to change the focus.  Please do periodically check to see that the focus position is still where it needs to be.

BATTRIES:  Keep extra batteries full charged on hand.  In very cold weather you battery will not last more that 2.5 hours so plan accordingly.  Do not hesitate to replace you battery with a fresh one every two hours.

SHOOTING MODE: Shoot in RAW (Full RAW – some of the newer cameras have sRAW, compressed RAW, etc. – please avoid these settings).  Shooting in full uncRAW will give you the best post processing options.

SET YOUR CAMERA TO MANUAL MODE

ISO: Verify your camera’s ISO capability.  Try different ISO settings from 400 to 2000 at wide-open apertures and 30 seconds for your shutter speed.  Check for NOISE.  Plan on using the highest ISO that gives you the best performance with minimum noise.  In cold weather the sensor of your camera will not get as hot so you will have slightly better performance as far as noise is concerned.

NOISE REDUCTION:  Long exposure noise reduction (LENR) will hamper your ability to capture images in quick sequence.  Remember that with LENR enabled it will take the camera as long to write to the CF or SD card as the exposure duration was.  So if your exposure was 30 second the camera will take another 30 seconds before you can shoot another image. My preference is to turn this feature off. High ISO noise reduction:  If you are shooting RAW files this has no impact.

LCD DISPLAY: Set your LCD review brightness to low and to 4 seconds or less.  A bright LCD can be deceptive and show the Aurora brighter that is was photographed and leading to major disappointments.

APERTURE:  You will be using the widest aperture of your lens.  Do not be concerned with Depth of Field, as you will be shooting with your focus set at infinity. Since most if not all your subjects are at a fair distance they will be in focus. The faster your lens the better, giving you the faster shutter speeds

SHUTTER SPEED:  This will depend on the brightness of the aurora, the aperture of the lens and the ISO setting of your camera. A good place to start for a moderate aurora is 30 seconds at ISO 400 and f 2.8, you can adjust from there by viewing your LCD screen. For your aurora photography where you include stars you should use the same principals as in star photography.  In this case you do not want star trails so you need to limit your shutter speed to 30 seconds or less for wide-angle lenses. However a 50mm lens exposed for 15 seconds will start showing star trails.  Use the 500 rule as a rough guide - 500 divided by the focal length to get your maximum exposure time before visible trailing occurs.

TRIGGERING: Set your camera for mirror lock-up if using a DSLR. Connect your cable release.  If you do not have one, use the camera’s self-timer.

SUPPORT:  Set up on a sturdy tripod and compose. 

Once you have your composition step away from the camera and cover the viewfinder if you are using a DSLR - black gaffer’s tape or use the internal cover if your camera has one.  You do not want stray light entering the body through the viewfinder. As a last pointer, condensation on your lens can pose a small problem so use a lens warmer.