Yellowknife's geographical location and light-pollution free landscape make it one of the most reliable places to view and photograph the aurora borealis, says Emmy-nominated astronomer Jose Francisco Salgado.

At a well attended presentation Wednesday at the Prince of Wales Northern Heritage Centre, Salgado explained the science behind the aurora to more than 70 people.

SA国际影视传媒�Yellowknife is just beneath the aurora oval, so we can see it in all directions of the sky,SA国际影视传媒� Salgado told Yellowknifer.

Viewers in Yellowknife are uniquely positioned to see the lights directly overhead with a 360 degree view, compared to southern locations where the viewer must look only north to see the aurora.

The lights, pulsating green, magenta and sometimes yellow and blue, are highly visible because of Yellowknife's semi-arid and subarctic climate, he said. The glowing lines are the byproduct of the earth's magnetic field reacting with solar activity.

The lights themselves are the product of the earth's magnetic field, rendered visible by solar activity and gases like oxygen and nitrogen. Oxygen emits green light, while nitrogen emits the magenta hues visible on highly-active nights. At high altitudes, oxygen glows red, and early SA国际影视传媒渟unlitSA国际影视传媒� auroras produce blue light at dusk.

Salgado conducts aurora photo and science tours outside of Yellowknife, combining his love of astronomy and science with art. He recently shot an aurora production in Yellowknife titled Wondrous Light, and out of 45 nights that Salgado has chased the northern lights, they have been active.

SA国际影视传媒�The aurora is so reliable from Yellowknife. You can see it almost on a nightly basis,SA国际影视传媒� Salgado said.

Salgado's advice to viewers and new photographers is to have patience and head away from the city's light-pollution to maximize viewing. The aurora comes and goes, and could be faint before becoming bright and active, he said, adding that the peak time to watch the lights is after midnight.

SA国际影视传媒�The landscape is beautiful as well, I love the night sky in the context of where I'm shooting from as well,SA国际影视传媒� he said.

Salgado is an astronomer, photographer, visual artist and public speaker. In 2006, he was nominated for an Emmy Award for his work on the show Nuestra Galaxia.