planets on display
The swiftest planet in the Solar System returns to the dawn skies this month – make sure you’re in the right place to see it
Your chance to catch a good glimpse of Mercury before the Sun obscures it again
It seems like an age since Mercury watchers had anything to smile about. The closest planet to the
Sun has been hard or impossible to see in the sky for months, either too close to the Sun to be seen or even hidden behind it. But finally this enigmatic, Sun-baked world is on view again, visible in the morning sky as a copper-hued star that is bright enough to be seen easily with the naked eye.
At the start of our observing period Mercury will be rising in the southeast at around 6:30am, an hour-and-a-half before the Sun. Observers with the lowest, flattest and least obstructed horizons in that direction will enjoy the best views, because Mercury’s close physical proximity to the Sun means it never strays far from it in the sky, so it never climbs very far up above the horizon. If you have trees, tall buildings or hills to the southeast of your usual viewing location you might like to consider a trip to somewhere with a more favourable view if you are set on seeing little Mercury.
The best time to see Mercury will be around midDecember. Mercury will be 21 degrees from the Sun – about as far as it ever gets – and should be easy to see with the naked eye. If you don’t spot it straight away, don’t worry; many people, even those who consider themselves to be experienced observers, often need a little time to find it. Once you have found it – and don’t worry if you need to sweep the sky with a pair of binoculars to track it down – you’ll find you can go back to it easily again and again.
Mercury isn’t alone in the sky this month – it has some very famous and regal company. Jupiter, considered by many to be the king of the planets, lies down to Mercury’s lower left, very close to the horizon, while Venus, the brightest planet by far, will be blazing brightly to the upper right of Mercury.
On the mornings of 22 and 23 December
Mercury and Jupiter will have a close encounter of the celestial kind where they will shine very close together in the sky. In fact, they’ll be so close – just a degree, or a Moon’s width, apart – that they will both fit in the same binocular field of view, and even in a telescope’s low-power eyepiece’s field of view too. However, the pairing will be very low in the sky, so don’t be too disappointed if you don’t manage to see this conjunction; you’ll have other chances.
Few probes have visited Mercury, but one is en-route right now. ESA’s BepiColombo probe blasted off in October. It will arrive at and begin to study Mercury in 2025, after flying past Earth and Venus along the way.