Space and astronomy highlights in 2023

Meteor showers, wandering planets, icy comets, eclipses, supermoons and much more – there's plenty of exciting astronomical phenomena to see in the night sky in 2023.

Check out the space and astronomy highlights to look forward to this year with astronomers from the Royal Observatory Greenwich. If you want to find out more, be sure to bookmark the monthly astronomy highlights blog and subscribe to the Royal Observatory Greenwich on YouTube.

Written by Tania de Sales Marques, Dr Greg Brown, Dr Affelia Wibisono and Jessica Lee

January

A dark photograph of the night sky with a horizontal flash of purple light from a meteor

See the Quadrantid meteor shower

The new year kicks off with one of the strongest meteor showers of the year, the Quadrantids. They're known for their 'fireballs' – meteors that appear brighter than even the brightest planets.

This shower reaches its maximum on the night of 3 January and the morning of the 4th, and potentially up to 110 meteors can be seen in an hour during the peak. However, this year the Moon will almost be full and its bright light will drown out many of the fainter meteors.

Wrap up warm and get to a dark spot away from light pollution to get the best out of this shower. Fill your view with as much of the sky as possible. If you think you see a Quadrantid meteor, you’ll know by tracing its path backwards and seeing if it passes through the northern part of the constellation Boötes, the radiant point from which the meteors will seem to originate.

Image: A Colourful Quadrantid Meteor by Frank Kuszaj, Astronomy Photographer of the Year 2021

Image of spherical planet with highlights and lines/ridges of blue and yellow

See the inner planets of the solar system (Venus and Mercury)

While both Venus and Mercury are bright enough to be seen with the unaided eye, with both being closer to the Sun than the Earth is, they rarely get far from it in the sky – making them difficult or even dangerous to see at times. This is especially true for Mercury, which is smaller, fainter and closer to the Sun than Venus.

If you’d like to see these rocky worlds for yourself, your best bet is to wait for their greatest elongation. This is the time when each planet is furthest from the Sun, and therefore more likely to still be above the horizon when the blinding Sun has set.

Venus will reach its greatest eastern elongation around 4 June and its greatest western elongation around 23 October. In and around these times, Venus will be easily visible as an evening and morning “star” respectively.

For a greater challenge, try looking for Mercury’s greatest elongations: western (and therefore seen in the morning) around the 30 January, 29 May and 22 September and eastern (seen in the evening) around 11 April, 10 August and 4 December.

As with any observation close to the Sun, make certain you don’t look directly at the Sun and, if observing with a telescope or pair of binoculars, wait until after sunset or before sunrise to avoid accidentally pointing them at it.

Image by NASA

See a conjunction of the Moon and Mars

On 31 January, the Moon and Mars will appear to come very close together in the sky, in an event called a conjunction.

To view the conjunction, look towards the south-eastern sky after sunset in the direction of the constellation of Taurus. The Moon will be at waxing gibbous phase so it will be bright, and the Red Planet will appear just north of it.

This event is visible to the naked eye, but a pair of binoculars or a telescope will enhance your view. It’s also a great opportunity for astrophotography!

For some parts of the Americas, the view of the Moon and Mars will be slightly different, so that the Moon will appear to pass in front of Mars, hiding it for a bit. This is called a lunar occultation. It’s visible to the naked eye and will provide plenty of interesting shots for astrophotographers.

Image: Perseverance by Damian Peach, Astronomy Photographer of the Year 2021

February

Portrait image of long, light blue and white comet against a black starry background

Spot a comet

Keen sky watchers might remember the appearance of comet Neowise in our skies back in the summer of 2020. There’s a possibility of another comet appearance this January, with the somewhat less catchily named C/2022 E3 (ZTF) approaching us this month. This comet was discovered in March 2022 by the Zwicky Transient Facility, which regularly scans the sky and compares the images to spot anything that has changed- for example supernovae, or variable stars, or approaching comets!

C/2022 E3 (ZTF) is coming into the inner Solar System, towards the Sun. It will be at its closest approach to the Sun on the 12 January, and then at its closest approach to the Earth on 1 February (at this point it’s still over 40 million km away!)

C/2022 E3 (ZTF) is already bright enough to be visible through a telescope, and it will be getting brighter throughout the month. Images taken so far showcase its eery green glow, a product of UV radiation from the Sun illuminating the gases sublimating from the comet’s surface. At its brightest in our skies this comet still probably won’t be as impressive as comet Neowise, and you’ll need a very dark sky to spot it. However brightness estimates vary, and comet viewing is always unpredictable - some think it could be visible to the naked eye! This would mean it has a magnitude of around +6, about the absolute limit the human eye can see. Even if it’s only visible with binoculars or a telescope, you should definitely get out and try and spot it if you can. As this is a long-period comet with a 50,000-year orbit, this is your only chance to catch it!

There might be other opportunities to spot comets with a pair of binoculars or a telescope later in the year.

For example, 62P/Tsuchinshan will be approaching the Sun in late 2023, with its closest approach to the Sun on 24 December, and its closest point to the Earth on 30 January 2024. At this time of the year it will be within the constellation of Leo, but with a predicted maximum magnitude of 9 you’ll be unable to see this with the naked eye.

How to see Comet C/2022 E3 (ZTF)

Image: Comet C/2021 A1 (Leonard) by Lionel Majzik, Astronomy Photographer of the Year 2021

See some constellations at New Moon

On 20 February there will be a New Moon, which means the Moon won’t be visible in the night sky. This is a perfect time for stargazing without the extra light of the Moon.

In the early night, famous constellations like Taurus and Orion are bright towards the south. The Pleiades, sometimes called the ‘Seven Sisters’, can also be seen near these constellations. This is a small cluster of blueish stars easily visible even from light-polluted cities.

Image: M45 by Richard Sweeney, Astronomy Photographer of the Year 2021

March

Astrophotograph of the Andromeda Galaxy, showing a spiral of stars tinted from bluey-pink to white at the centre

Search for another galaxy

There is another New Moon on 21 March, which can be used to search for more deep-sky objects in the cosmos. Keep an eye out for the Andromeda Galaxy, which is the nearest galaxy to our own Milky Way Galaxy.

Just after sunset, if you look towards the north-west, the Andromeda Galaxy can be seen near to the Andromeda and Cassiopeia constellations. In dark areas away from city lights, this galaxy can be seen with a simple pair of binoculars or even the naked eye!

Image: Andromeda Galaxy: The Neighbour by Yang Hanwen and Zhou Zezhen, Astronomy Photographer of the Year 2022

Image of man standing looking at night sky, which has two bright lights close together which are Venus and Jupiter

See a conjunction of Jupiter and Venus

In early March two of the brightest planets in our sky, Venus and Jupiter (both easily visible to the unaided eye), will be about half a degree apart at their closest point, known as an appulse.

The conjunction itself occurs when the two share the same right ascension, a coordinate in space which is similar to longitude here on the Earth.

While the conjunction and appulse will occur during the daytime here in the UK on 2 March, the planets will still be very close together in the sky for several days either side. Even at their closest point, it will be difficult to fit both planets into the typical view of a telescope, so this is one of those times when a pair of binoculars is probably the best way to go.

Above the horizon already at sunset and setting a couple of hours later, Venus and Jupiter will be all but unmissable as the bright points of light in the southwest in the early evening sky. Take a look for yourself!

Image: Venus-Jupiter close conjunction by Laurent Laveder, Astronomy Photographer of the Year 2012

Watch out for equinoxes and solstices

You may have noticed that there are certain times of year when the days seem longer and other times when the nights never seem to end. The changes in the length of day and night are caused by the tilt of the Earth.

When the Earth orbits the Sun, at certain times of year the Northern Hemisphere is tilted towards the Sun and the Southern Hemisphere is tilted away from it. For the other half of the year, the reverse happens.

Equinoxes happen when neither hemisphere is tilted towards or away from the Sun and there are roughly equal hours of daylight and darkness. Solstices, on the other hand, happen when a specific hemisphere is tilted towards or away from the Sun, which makes long days or long nights.

You can keep an eye out for the equinoxes and solstices to notice how the length of day and night changes throughout the year. The two equinoxes happen on 20 March (Spring Equinox) and 23 September (Autumn Equinox) and the days and nights should roughly be the same length. For all of us in the Northern Hemisphere, the summer solstice will be on 21 June and there will be over 16.5 hours of daylight on this particular day! The winter solstice will be on 22 December, and there will be slightly less than eight hours of daylight.

Image: Comet Neowise over Stonehenge by James Rushforth, Astronomy Photographer of the Year 2021

April

PS-66052-9_Milky Way and Meteor at Porthgwarra © Jennifer Rogers.jpg

Look out for the Lyrid meteor shower

The Lyrids will be visible from 14-30 April, peaking on 22-23 April.

Although not the most active meteor shower, the Lyrids can sometimes display meteors with bright dust trails that glow for several seconds.

The best time to look for the Lyrids, if the weather permits, is in the early hours of 23 April. This year, observers are in luck as the Moon will be below the horizon before midnight, which increases the chances of seeing the dimmer meteors.

The source of the Lyrids is the Comet C/1861 G1 Thatcher, which orbits the Sun once every 415 years. It is the oldest recorded meteor shower still visible today, and was first recorded in 687 BCE.

Image: Milky Way and Meteor at Porthgwarra by Jennifer Rogers, Astronomy Photographer of the Year 2020

The planet Jupiter with its moons Ganymede and Calisto

See the JUICE mission launch

Jupiter will soon have a new orbiter studying it and some of its largest moons. The European Space Agency’s JUpiter ICy moons Explorer (JUICE) mission is scheduled to launch on an Ariane 5 rocket on 13 April 2023.

The journey for JUICE is long: it will take over seven years to reach its destination. JUICE will spend around two years orbiting Jupiter and making close flybys of Europa, Ganymede and Callisto. It will then spend the rest of its planned lifetime orbiting Ganymede, which will make it the first spacecraft to orbit a moon that is not our own.

On board JUICE are 10 cutting-edge instruments that will help confirm if some or even all three of Jupiter's moons have oceans of liquid water beneath their crusts. If so, could there be life there?

More about JUICE

Image: Jupiter, Ganymede and Callisto by Luke Gulliver, Astronomy Photographer of the Year 2021

Look out for the Eta Aquariid shower

The Eta Aquariid meteor shower is active from 19 April-28 May, peaking around 6 May and expecting to produce up to 50 meteors per hour.

This shower is more visible for the Southern Hemisphere and will appear low in the sky in the Northern Hemisphere (such as the UK) in the early hours pre-dawn.

Nevertheless, it should still be possible to see the shower in the eastern sky, even when the radiant is below the horizon.

Look towards the East to spot the star Eta Aquariid in the constellation of Aquarius, after which the meteor shower is named. The source of the meteor shower is the famous Comet Halley, which is visible from the Earth every 75-76 years.

Image: Eta Aquariid Meteor Shower in Mount Bromo by Justin Ng, Astronomy Photographer of the Year

July

Night skyscape showing the Perseid Meteor Shower and the Milky Way, with stars appearing to cascade down to a scene of green fields and lakes

Catch the Perseid meteor shower

July and August will see the Perseid meteor shower, caused by the debris stream from the comet Swift-Tuttle.

It’s a highlight of many meteor lovers’ calendars due to its high hourly rate and bright meteors.

In 2023 the Perseid meteor shower is active between 17 July and 24 August, with the shower peaking 12-13 August. Fortunately, the maximum is about three days before the New Moon, so conditions will be favourable.

The shower will radiate between the constellations Perseus and Camelopardalis, so find a dark spot and look there for the best chance of seeing some Perseid meteors.

Image: The Perseid Meteor Shower and Milky Way over Petworth Deer Park by Kush Chandaria, Astronomy Photographer of the Year 2022

Never miss a shooting star

August

OM-21864-1_The Moon And the Shard © Mathew Browne.jpg

Spot a supermoon

The Moon revolves around the Earth in an elliptical or oval-shaped orbit, which means that during its orbit it travels from closest approach (perigee) to furthest distance from us (apogee).

When the Moon is at perigee and it’s at a Full Moon or New Moon phase, we call it a supermoon. A Full Moon at perigee will appear 14 per cent bigger and 30 per cent brighter than a Full Moon at apogee, but since we can’t really compare the two side by side, most people will not notice much difference.

There will be two Super Full Moons in 2023, both in the same month: one on 1 August and another on 31 August.

Image: The Moon and the Shard by Mathew Browne, Astronomy Photographer of the Year 2020

The planet Saturn photographed using a telescope

See a planet at opposition

Saturn moves into opposition on 27 August. This means that it’s positioned opposite to the Sun in the sky, fully illuminating its face so that it appears at its brightest.

Neptune and Jupiter do the same on 19 September and 3 November respectively. These moments are potentially great opportunities for astrophotography, but it may be worth trying your techniques out on Saturn first, because Neptune will be a real challenge!

Uranus will also be at opposition on 13 November.

Image: Saturn at its Best by Damian Peach, Astronomy Photographer of the Year 2021

October

A silhouette of a person looking out to sea at night, with rocks and stars framing them

Sight some Orionid meteors

With a maximum rate of around 25 meteors per hour, the Orionid meteor shower, peaking around the night of 21 October, features fast meteors which can leave persistent trains. With the Moon in 2023 around First Quarter during the peak, conditions should be quite good to spot the Orionids.

As with other showers, fill your view with the sky. Take a look for the bright streaks of light that come from small grains left behind by the famous Halley’s Comet as they crash into the Earth’s atmosphere.

Image: The Star Observer by Antoni Cladera Barceló, Astronomy Photographer of the Year 2021

Close up computer rendering of round metallic asteroid in space

Watch the launch of NASA’s Psyche mission

Over the last few years, we’ve been lucky enough to experience visits to planets, comets and more, facilitated by robots sent to these distant locations by space agencies like NASA and ESA. This year is no different, and one of the more interesting missions is NASA’s Psyche mission.

Psyche is an asteroid in the asteroid belt, a region of space between Mars and Jupiter, containing millions of bits of rock and metal, and it’s the latter that this new mission is looking into. Iron is an extremely important part of our solar system, with all of the rocky planets having a core made mostly of it. Could Psyche be a fragment of the core of a planet that never quite formed? Could this provide an insight into the formation of our own planet Earth?

While Psyche won’t reach its target until 2029, its launch, currently slated for October 2023, is something to look out for!

Illustration of Psyche by NASA

See a partial lunar eclipse

On 28 October 2023, the UK will see a partial lunar eclipse.

A partial lunar eclipse happens when the Moon passes through the Earth's penumbra (the outer region of the Earth’s shadow), and only a section of it passes through the umbra (the darkest part of the Earth’s shadow).

From the UK we’ll only see a small fraction of the Full Moon pass into the umbra. At its maximum, which occurs at 21:15, just 12% will be in shadow. The partial eclipse will be visible throughout all of Europe, Asia, and Africa, and western Australia.

Image: HDR Partial Lunar Eclipse With Clouds by Ethan Roberts, Astronomy Photographer of the Year 2020

December

Image of meteor shower with around 30 meteors in the sky over a large observatory telescope

Spot the Geminid meteor shower

The Geminids, with a possible hourly rate of 150 meteors per hour, are one of the best meteor shower displays you can see all year.

Reaching maximum on 14-15 December, the Moon will be a waxing crescent on the peak, making viewing conditions favourable.

As with most showers your best chance to see meteors is in the early hours of the morning around the peak, though a good number should be seen any time from a few hours after sunset.

Fill your view with the sky and wait for the lights to appear. And, given this is a midwinter wonder, don’t forget to wrap up warm!

Image: Geminids over the LAMOST telescope by Yu Jun, Astronomy Photographer of the Year

Main image: The Guardians of Scorpio © Vasyl Yatsyna Astronomy Photographer of the Year 2021