Rare 5 planet line-up best viewed this week

The next few days present your best chance to catch a rare view of five planets lined up in a row across the sky.

For the past two weeks, Mercury, Venus, Mars, Saturn and Jupiter — all five planets visible to the naked eye — have all been visible at the same time in the southern sky before dawn. Officially, you'll be able to catch the planetary line-up until Feb. 20. It's the first time the five planets have been visible in a row since January 2005.

There are two things this week that will enhance your view:

• The crescent moon will appear close to Venus and Mercury early Saturday morning, providing a great photo op.
• Mercury will be at the highest position in its orbit on Sunday.

Mercury is normally "the elusive one to see," says astronomy writer and educator Gary Boyle. After Feb. 7, it will start heading closer to the horizon — where it's harder to find — before disappearing.

The best time to look is an hour before dawn, recommends Boyle, who lives in South Mountain in eastern Ontario and runs the astronomy website Wonders of Astronomy. He suggests that around 6:30 a.m. local time will work for most Canadians, but that will get a little earlier every day as spring approaches.

You'll want to find somewhere with a clear view of the south-southeast horizon, as Mercury will be quite low even at its highest point.

The easiest objects to find will be the Moon and Venus in the southwest, the two brightest objects in the night sky. Mercury will be a little bit east of Venus.

"Once you find Venus and the moon, you'll see Mercury no problem," Boyle says.

If you imagine a line connecting Mercury and Venus and continue extending it up and across, you should find the other planets lined up across half the sky, with Jupiter, which is extremely bright, on the other end of the line.

"It's just a beautiful, scenic view," Boyle says.

He added that you might have a little trouble finding Saturn or Mars, which are not as bright as the other planets, but using a chart of the night sky can help.

Of course, you'll only be able to see the planets if the weather gives you clear skies. But if they don't, try again the next night, Boyle suggests.

The planets will actually align again later this year — in August. But at that point, they'll be visible in the evening sky, and Mercury and Venus will be too low in the sky to see easily from northern latitudes, the astronomy website EarthSky warns.

After that, the next viewing of five planets at once isn't until October 2018.

• Night sky photography tips and tricks