Look up for four planets in a line.

Four planets will be in a visible line stretching from the horizon to overhead in the evening sky next week.

This happens about once a year as Mercury and Venus make their way around to the same side of the Sun.

Venus will be the brightest shining in the west about 1/3 of the way up the dome of the sky.  Look for Mars nearly overhead (astronomers call this point zenith) with its noticeably orangey-red color.

You'll find Jupiter then, a bit dimmer, Mercury very close to the horizon. For the best chances of seeing the pair, find a location with a clear western horizon.  Elevation helps too.

You may remember seeing a much brighter Jupiter.. This is because stars and planets appear dimmer as they draw closer to the horizon because we are looking through so much more atmosphere.  This week, about the same brightness as Mars. 

This week, Mars is shining through about 1 layer of atmosphere, about 50 or 60 miles thick. Around 8 p.m., there is 13 times more atmosphere between you and Jupiter.  As Jupiter sets about 30 minutes later, this increases to more than 40 times as much atmosphere.

Above Jupiter you'll find dimmer Mercury. This is a treat because tiny Mercury spends most of its time, in front of, behind, or too close to the Sun to be visible.

Planets disappear from our sky as they pass behind the Sun, or get lost in the Sun's glare as they pass in front. Each reemerges in the morning sky after a few days for speedy planets like Mercury and after a few months for the outer planets like Jupiter.

You may have read that there are five planets "visible" during this last week of March. Uranus is the fifth planet, a bit up and to the left of Venus. Uranus  is about 10,000 times dimmer than Venus and requires a very good set of binoculars or a moderate sized telescope to see.

While you are spotting these four planets, look for the ecliptic or the line planets form across  the sky.  This is the plane of the solar system that the planets orbit along.

That tilt differs depending on you location on Earth. Every degree of latitude added as you move north, adds a degree of tilt to the ecliptic. For example, the ecliptic is tilted 10 degrees more in Montréal, Canada (45.5º N latitude) than here in Raleigh (35.8º N latitude).