AuroraMAX - FAQ

The live camera turns on automatically once the Sun sets below the horizon in Yellowknife. The countdown clock on our web page gives the time remaining before the camera is activated. As the winter solstice approaches in the month of December, the camera will turn on several minutes earlier each day, since darkness falls earlier.

The AuroraMAX Observatory's main camera is an all-sky imager, which gives a 180-degree field of view to capture the entire night sky so that you don't miss any auroras. (In Yellowknife, auroras typically light up the sky from one horizon to the other, and very often seem to be right over the observer's head as well!) Here's a tip to get used to the image: imagine lying on your back and being able to see all around you—even behind you.

If you don't see auroras right away, be patient. Auroras tend to come in waves, called auroral substorms. You may have logged on in between two substorms or before it is dark enough to see the northern lights. Other factors can also reduce visibility locally, including clouds, rain or snow on the observatory's Plexiglas dome. (You may want to check the weather locally to see if weather might be impeding your view of the auroras.)

The full Moon can make the auroras appear paler and less colourful. The Moon also can also reflect off the observatory's dome and snow on the ground.

This montage shows the AuroraMAX Observatory's main camera in the foreground, along with one of its images of an aurora (round). While most skywatchers are used to viewing a small section of the northern lights as seen in the background image, the 180-degree AuroraMAX camera actually captures the entire aurora as it stretches across the night sky from west to east.

You might be missing a Flash plug-in to run the videos. You can either download the plug-in free of charge from the following website http://get.adobe.com/flashplayer/, or watch the videos in HTML (on the main page www.asc-csa.gc.ca/auroramax, scroll down to the bottom of the page and select "HTML version").

The AuroraMAX replay is a time-lapse video of the previous night's auroras condensed into one or two minutes.

AuroraMAX's main camera shoots a 180-degree view of the sky, which produces a circular image. The circumference of the circle is actually the horizon all around the camera (if you look carefully, you will see the tree tops even in the upper portion of the image). 

Aurora usually begin to appear in the hours following dark locally when skies are clear, and tend to intensify around midnight. Visit Astronomy North for the aurora forecast for tonight and the coming days. Local weather and sky conditions in Yellowknife (including sunrise and sunset) are available from the Government of Canada's Weather Office.

Northern skywatchers see the aurora more frequently because of the position of the auroral oval, a crown of geomagnetic activity around the north and south magnetic poles. Communities located beneath the oval regularly see bright auroras.

Yellowknife's latitude (62 degrees North) and semi-arid subarctic climate (which averages less than 300 mm of precipitation annually) make for ideal viewing conditions for the northern lights. The auroral oval is often found directly overhead, resulting in auroral displays almost every night, even when the solar wind is calm.

During periods of increased solar activity, intense solar winds will cause the auroral oval to stretch like a rubber band and expand southwards. When this occurs, southern latitudes are treated to bright auroras.

On your home computer! The AuroraMAX Observatory is a virtual facility that provides aurora enthusiasts everywhere with instant access to Yellowknife's northern lights via the Internet.

The northern lights (also known by their Latin name, the aurora borealis) are a natural display of light commonly seen in the northern sky (auroras in the southern hemisphere are known as the aurora australis). Auroras occur when charged particles from the Sun collide with gas molecules in the Earth's atmosphere, producing energy in the form of light.

The solar wind is a continuous flow of charged particles from the Sun.

As the solar wind flows past the Earth, its charged particles travel along magnetic field lines that descend into the Earth's atmosphere near the north and south magnetic poles. These particles (electrons and protons) collide with oxygen, nitrogen and other molecules of gas in the atmosphere, resulting in auroras.

A substorm is a brief but intense surge in geomagnetic activity that produces very bright, fast-moving auroras.

The colours of the aurora are determined by the composition of gases in the Earth's atmosphere, the altitude at which the aurora occurs, the density of the atmosphere, and the level of energy involved.

Green, the most common colour seen from the ground, is produced when charged particles collide with oxygen at lower altitudes (around 100-300 km). Occasionally, the lower edge of an aurora will have a pink or crimson fringe, which is produced by nitrogen molecules (around 100 km).

Higher in the atmosphere (300-400 km), collisions with atomic oxygen produce reds instead of greens. Since the atmosphere is less dense at higher altitudes, it takes more energy and more time to produce red light (up to two minutes), whereas green light can be made quickly at lower altitudes (about one second).

Hydrogen and helium can also produce blue and purple, but those colours tend to be difficult for our eyes to see against the night sky.