Sky watchers in Western Canada will have a chance to observe a total lunar eclipse early Saturday morning — for the last time until 2014.
The Earth's shadow will completely cover the moon for a little over 50 minutes starting 6:05 a.m. PT , astronomy magazine Sky and Telescope reports.
Why does the moon turn red?
The moon turns orange, red or brown during the peak of a total lunar eclipse. Normally, it appears grey or white as it reflects sunlight that shines on it directly — a combination of all colours of the spectrum visible to our eyes. However, during a total lunar eclipse, the Earth's shadow blocks the direct sunlight. Any light that still reaches the moon must first pass through the Earth's atmosphere. The atmosphere filters out most of the blue light so that mainly the red light makes it to the moon.
According to NASA, the peak of the eclipse, when the moon will appear red or orange, will take place at 6:30 a.m. PT. That's roughly 1½ hours before the sun is scheduled to rise and the moon is scheduled to set in Vancouver.
The peak takes place well after dawn for most of Canada. However, residents of Central Canada may be able to see the earlier stages of the eclipse, when the moon dims slightly as it enters the Earth's shadow. That will start to happen at 3:33 a.m. PT.
Unlike solar eclipses, lunar eclipses are perfectly safe to look at without any eye protection.
People in Hawaii, Australia and East Asia will have the best views of the eclipse, which takes place during their night. This is the second total lunar eclipse of the year — another one took place in June, but during the daytime in North America. It was visible in Europe, Asia and Africa.
The next total lunar eclipse visible from North America won't take place until April 15, 2014, NASA says. However, a partial lunar eclipse will be visible in Eastern Canada around dawn on June 4, 2012, Sky and Telescope magazine reports.
NASA is taking advantage of Saturday's eclipse to take measurements with its Lunar Reconnaissance Orbiter. The unmanned spacecraft, which has been orbiting the moon since June 2009, will measure how quickly areas of the moon's day side cool off during the eclipse. The rate of cooling will depend on the composition, density, and rockiness of the lunar surface.