SOMBA K'E/YELLOWKNIFE
Thursday will be a dark day in Yellowknife, and not merely because Environment Canada forecasts clouds with rain.

From 2:29 until 5:02 p.m., the city will experience a partial solar eclipse.

Stephen Bedingfield peers at the sun using special solar filter binoculars that protect his eyes during a total solar eclipse in the Sahara desert south of Julu, Libya, on March 29, 2006. The amateur astronomer has pursued total solar eclipses around the world, traveling to Ethiopia, Libya, Australia, Japan and French Polynesia to observe the rare celestial phenomena. - photo courtesy of Stephen Bedingfield

The cosmic event will peak shortly before 4 p.m., at which time more than two thirds of the sun will be darkened by the moon as it passes between Earth and the centre of the solar system.

Yellowknife is among the best places to view Thursday's partial eclipse, said Stephen Bedingfield, a local member of the Royal Canadian Astronomical Society.

Bedingfield plans to view the eclipse from New Mexico, where he is attending an astronomy conference. From that vantage, only 31 per cent of the sun will be obscured by the moon.

"The North is a much nicer place to view it," he said.

The eclipse will be visible throughout the NWT up to Banks Island and Victoria Island.

From Yellowknife's perspective, 71 per cent of the sun will be blacked out by the moon as the eclipse peaks at 3:48 p.m.

Further north in Gjoa Haven and Cambridge Bay, the sun will be 74 per cent obscured at the peak time there. Above Edmonton, 64 per cent of the sun will be covered.

Even though the sun will be semi-obscured during tomorrow's partial eclipse, it is not safe to observe the phenomenon with the naked eye, Bedingfield warned.

Improvised protective devices such as dark sunglasses and Mylar sheets will not protect the eye either, he added.

"The sun may look dimmer, but that doesn't stop the ultraviolet light that burns the retina," he said. "You don't feel it."

The only way the eclipse can be safely viewed is by wearing proper solar filters available from specialty science hobby stores, No. 14 welder's goggles, or by witnessing it indirectly using the pinhole projection method, he said.

The simplest way to create a pinhole projector is by taking two thin, firm pieces of white cardboard and poking a tiny hole in the centre of one of them. Hold the cardboard with the pinhole toward the sun such that light can pass through and onto the surface of the other piece of white cardstock held below it.

Viewers will then be able to see an inverted image of the crescent sun by looking at the cardboard screen without having to stare skyward, said Bedingfield.

Watching the eclipse without taking appropriate precautions could result in permanent eye damage or blindness, he cautioned.

Stephen Kirkham, science department head at Sir John Franklin High School, said he planned to approach his school's auto shop earlier this week to inquire about borrowing No. 14 welder's glasses for his physics students to use to view the partial eclipse.

The orbit of the planets and their satellites touches on the Grade 11 curriculum, he added.

"It's one of these things that we're going to have to work around because it's so rare," he said. "It encourages the type of visual three-dimensional thinking involved in Physics 20."

At St. Patrick High School, teacher Christina Silzer said she also plans to discuss the partial solar eclipse with students in her knowledge and employability class.

Grade 6 classes study a unit on the solar system as part of their science curriculum, as well.

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