Mercury Magic in March

Mercury is visible low in the western sky during March, but be quick!  It isn’t there for long.

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On 20 March, Mercury will shine low in the west as the sky darkens about 30 minutes after sunset. It’s going to be a lean time for planet hunters in the coming few months, as the brighter neighbours in our Solar System move closer to the Sun. Only Jupiter is hanging in there, moving lower in the southwest at dusk.

But March will bring the elusive planet Mercury back into the western sky, low down near the horizon soon after sunset.

Being the closest planet to the Sun, Mercury never strays out of the twilight sky and you have to be in the right place at the right time to catch it. So make the most of its appearance this month, as it won’t be as well placed in the evening sky for another year.

Have a look towards the west, starting about 30 minutes after sunset. Around the time of the spring equinox, due this year on 20 March, sunset is around 6 pm virtually everywhere in the country. Look in the brightest part of the twilight and as the sky gets darker you should be able to see a bright starlike point just a few degrees above the horizon.

Mercury
Mercury, low in the west during its last evening appearance in April 2023. This year’s show should be similar. Credit: Mark Hardaker

You’ll need an unobstructed and clear horizon, and if there are any clouds around you might need to wait till they drift away. Binoculars will help. Mercury will become easier to see as the sky gets darker, but it also sinks lower towards the horizon as well. And please be careful. Do not try looking before sunset; you won’t see Mercury and you could damage your eyesight if you accidentally look at the Sun.

When to Look

You might first spot Mercury very low on the horizon on 12 March, when a thin crescent Moon will help you find the planet.  Draw a line from bright Jupiter in the southwest, down through the Moon, continuing to the horizon. Mercury will be on that imaginary line, just a few degrees high.

Viewing becomes easier a few days later and on the equinox day itself, 20 March, Mercury will shine at magnitude -0.6 and should be easily seen with the naked eye.

As the month progresses, Mercury grows fainter and lower in the sky, until by 1 April it will be tricky to find even with binoculars. Only ten days later, Mercury will depart from the evening skies and pass between the Earth and the Sun.  It will reappear in the morning sky during May but will be virtually impossible to see in the bright morning twilight.

Viewing Tip

Today’s smart phones, with their accurate astronomy apps, can help you to locate the stars and planets in the sky. Apps such as Stellarium, Sky Safari and Sky Guide will line you up towards the west and show you when and where to find Mercury, as well as showing the nearby constellations in the sky. Good luck.