Planetary Conjunctions: Mercury, Saturn, Venus, Mars

This March, three planetary conjunctions will take place. Learn how and when to see them.

What is planetary conjunction?

In simple words, a planetary conjunction occurs when two or more planets appear close to each other in the sky. Such proximity of planets is an optical illusion — in reality, they are very far away from each other.

From an astronomical point of view, a conjunction happens when celestial objects share the same right ascension * or ecliptic longitude ** in the sky.

*Right ascension is the equivalent of longitude on the Earth’s surface projected onto the celestial sphere.

**Ecliptic is an imaginary line that marks the Sun’s apparent path across the sky during a year. Ecliptic longitude is measured along the ecliptic eastwards from the Sun’s position at the March equinox.

While the first definition is more common, it isn’t very precise. In fact, it describes a close approach (small angular separation) of space objects — an event that usually takes place near a conjunction. But don’t confuse these events! A close approach isn’t necessarily a conjunction.

Usually, the distance between objects during a conjunction varies from 0.5° to 9°. To get it better, imagine that 0.5° is the average width of a Full Moon disk. Sometimes planets come even closer — last time it happened with Jupiter and Saturn in 2020 when they appeared less than 0.1° apart. Such an event is called the Great Conjunction and provides a spectacular show for stargazers.

A conjunction can include other celestial objects besides planets — for example, moons, asteroids, or stars. In our article, we list the upcoming conjunctions of the Moon and planets, so you can learn which planet is close to the Moon tonight.

Planetary alignment

Some people confuse a planetary conjunction and a planetary alignment, sometimes referred to as a “planet parade.” A conjunction implies a shorter than usual distance between objects in the sky, while an alignment means that planets line up in a row in the same area of the sky, as seen from the Earth.

March conjunctions

You might miss the exact moment of conjunction depending on your timezone. But don’t get disappointed; even the night after the conjunction, objects you’d like to see will still be positioned quite close to each other.

March 2: Mercury-Saturn conjunction

On March 2, 2022, at 15:48 GMT (10:48 a.m. EST), Mercury will pass only 0°41' to the south of Saturn, making it the closest conjunction of these two planets in 2022. The objects will be located in the constellation Capricornus, shining with a visual magnitude of -0.1 (Mercury) and 0.7 (Saturn).

The best time to see the planets is in the morning when civil twilight begins. You’ll need a clear horizon and a pair of binoculars to get a better view. But if you don’t own one, it’s fine — the event is visible with the naked eye. The Moon won’t interfere with observations reaching its new phase the same day.

March 16: Venus-Mars conjunction

On March 16, at 03:12 GMT (March 15, 10:12 p.m. EST), Venus and Mars will appear closest to each other this year, separated by only 3.9°. The luminous Venus that recently reached its greatest brightness will have a visual magnitude of -4.5. The Red Planet won’t be nearly as bright, having a magnitude of only 1.2, but still visible with the naked eye.

Like Mercury and Saturn, Venus and Mars will be best visible shortly before sunrise in the constellation Capricornus. Observers from the Southern Hemisphere will have a better view as the planets there rise above the horizon earlier and climb higher before dawn.

March 29: Venus-Saturn conjunction

On March 29, at 00:53 GMT (March 28, 7:53 p.m. EST), Venus will pass near another planet, Saturn. Their conjunction will be closer than the previous one; the distance between planets will be 2°09'. Venus will slightly lose in brightness, shining with a magnitude of -4.3. Saturn, in its turn, keeps a brightness of 0.7.

Look for the objects in the constellation Capricornus in the morning hours. By the way, Mars will be located nearby, as it follows Venus throughout March. All the planets are visible with the naked eye, but you can use a pair of binoculars to see more details — like Venus’ phase or Saturn’s rings.

Now you know how and when to spot the planets close together this month. If you enjoyed this article, share it with your friends.

We wish you clear skies and happy observations!

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