Astronomy conjunctions: upcoming events and how to see them

When the Moon, planets and stars come together to form a conjunction, the results can be spectacular. Find out which conjunctions to look for in the night sky.

Conjunction: what a funny-sounding word it is, yet in the field of astronomy this phenomenon can give us some wondrous night-sky sights, ranging from naked-eye views through to binoculars and even telescopic viewing.

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There are usually a few beautiful conjunctions to see in the night sky – or early morning sky for that matter – each month, and below we’ll look at some of the best coming up over the next few weeks.

For more conjunctions and stargazing advice, listen to our Star Diary podcast, which reveals what to look out for in the evening and morning skies over the coming weeks.

You can also sign up to the BBC Sky at Night Magazine newsletter for weekly updates on what to see in the night sky.

A conjunction of the moon with Venus and Jupiter, Chanthaburi, Chanthabur, Thailand, 28 November 2019. Credit: Chakarin Wattanamongkol / Getty Images
A conjunction of the moon with Venus and Jupiter, Thailand, 28 November 2019. Credit: Chakarin Wattanamongkol / Getty Images

What is a conjunction in astronomy?

Generally speaking a ‘conjunction’ is the name given to two or more celestial objects close together in the night sky.

The most commonly observed conjunctions involve the Moon, often as a crescent in the evening or morning sky, along with any of the bright planets – Venus, Mercury, Mars, Jupiter or Saturn.

Read more observing guides:

You can also see conjunctions between the Moon and bright stars or even between the planets themselves, so there is quite a range of possible combinations.

Some involve more than two objects, such as when two planets are in conjunction and are joined by the Moon.

There are also times when incredibly close conjunctions set two objects in the same telescope field of view, or in really special cases, show Venus or Mercury transit across the face of the Sun.

You may already have come across the term in astronomy guides, yet if we went by its strictest definition then some events called conjunctions would probably not qualify.

A conjunction of the Moon, Venus, Mars and Spica, Azul, Argentina. Credit: Stocktrek Images/Luis Argerich/Getty
A conjunction of the Moon, Venus, Mars and Spica, Azul, Argentina. Credit:
Stocktrek Images/Luis Argerich/Getty

To be precise: a conjunction is a line-up of at least two celestial objects in the sky relatively close together that share the same Right Ascension (RA) or ecliptic longitude in the sky.

  • RA is the equivalent of longitude on Earth but projected onto the celestial sphere
  • The ecliptic is the plane of Earth’s orbit and appears to us as the apparent path of the Sun across the sky. Ecliptic longitude is measured along the ecliptic eastwards from the spring equinox

Even within astronomy there are different meanings of the word conjunction.

  • When a planet, either outer or inner, lies on the other side of the Sun to Earth it is said to be at superior conjunction
  • When an inner planet lies between Earth and the Sun it is at inferior conjunction
Tony Titchener captured this beautiful image of a crescent Moon and Venus on 27 February 20202, before lockdown began. Tony captured it on 27 February 2020 from Seaford, Sussex, UK using a handheld Nikon Coolpix 520 bridge camera. Credit: Tony Titchener
Tony Titchener captured this beautiful image of a crescent Moon and Venus on 27 February 2020. Tony captured it on 27 February 2020 from Seaford, Sussex, UK using a handheld Nikon Coolpix 520 bridge camera. Credit: Tony Titchener

When do conjunctions occur?

Often a conjunction will occur during daytime or when the objects are below the horizon, and this is where the definition becomes more relaxed.

If the objects are very bright, such as a crescent Moon and Venus, then daylight viewing can be possible, but if the objects have set below the horizon they won’t be visible.

So conjunction can be applied in quite a loose context to refer to objects that are viewable above the horizon in twilight or at night, even if they are not, at that point, at the exact moment of conjunction.

  • If the objects are at their closest, then this is known as an appulse: the minimum separation between two bodies that occurs just before or after true conjunction.

Conjunctions really capture our attention, which makes them ideal targets for public stargazing events, or for inspiring young astronomers and newcomers to look up at the night sky.

They are also easy to capture with a smartphone camera, giving more people the chance to preserve the moment and share with friends or on social media.

For more on this, read our guide on how to photograph a conjunction.

Moon, Venus, Jupiter & Mars Conjunction 8 Oct 2015, by Peter Louer
The Moon, Venus, Jupiter and Mars in conjunction, 8 Oct 2015. Credit: Peter Louer

Conjunctions to see in the night sky

Below we’ll look at some fascinating conjunctions coming up over the next few weeks between the Moon, planets and stars.

1-3 July: Venus and M44

In the early evening twilight have a go at a quite tricky encounter as Venus lies close to star cluster M44 and passes it on 2 July and 3 July.

It is highly likely that the cluster won’t be visible in the bright twilight but it’s worth looking for it! Mars lies the other side of the cluster to Venus and a bit further away, so if you don’t spot the cluster then see if you can spot Mars.

6 July: Moon and Pleiades

In the early onset of morning twilight look over towards the eater-northeast for the crescent Moon lying below the Pleiades star cluster, M45. If you look around 3am onwards you will see them rise and not long afterwards be joined by the Hyades star cluster and Aldebaran, the eye of the Bull.

8 July: Mercury and the Moon

Catch Mercury near the Moon early in July 2021 before it drops back into solar glare. Credit: Paul Money
Catch Mercury near the Moon early in July 2021 before it drops back into solar glare. Credit: Paul Money

Mercury moves into the morning sky but is very low in the morning twilight. On 8 July look towards the northeast morning twilight horizon for the crescent Moon with Mercury, roughly 45 minutes before sunrise. Mercury is always brightest at the end of its morning apparition, so it improves before it drops back into the solar glare later in the month.

8-20 July: Outer planets

With Venus and Mars in the evening twilight and Mercury in the morning twilight we find the giant outer planets Saturn, Jupiter, Neptune and Uranus spread out through the night, giving us a chance to view all in one night!

11-12 July: Venus, Mars and the Moon

Keep an eye on Venus and Mars mid-July. Credit: Paul Money
Keep an eye on Venus and Mars mid-July. Credit: Paul Money

The slim crescent Moon lies to the right of Venus with Mars to the left of Venus. Then Venus and Mars meet on 12 July for a conjunction where Venus will guide you to the fainter Red Planet for a great visual and photo opportunity. For added interest the slim crescent Moon lies to their upper left.

11-18 July: Neptune

Requiring at least 7×50 binoculars or larger or a telescope, from 11-18 July Neptune lies close to the star HIP 116402 ,which is mag. +7.2, slightly brighter than mag. +7.8 Neptune.

HIP 116402 is the left hand star of a diamond of stars that Neptune passes through over the next few months and this diamond of stars lies below the Circlet asterism of Pisces.

17 July: Pluto

Keep an eye on Pluto from July 2021 onwards. Credit: Paul Money
Keep an eye on Pluto from July 2021 onwards. Credit: Paul Money

One for a large telescope now, as Pluto reaches opposition and so is viewable all night. It is magnitude 14.3 so needs a good chart and large telescope indeed! It lies in Sagittarius in a quite bland area of sky to the west (right) of M75.

For more info, read our guide on how to observe Pluto.

21 July: Mars, Venus and Regulus

See how long you can spot Mars as it drops deeper into the evening twilight, as Venus moves away to the left from it. On 21 July Venus lies above right of the star Regulus. This star is normally an easy naked eye bright star but deep in the twilight is a different story, so the bright planet may be your only chance to spot Regulus before it follows Mars and is lost to view.

24 July: Moon, Jupiter and Saturn

The Moon is full on the morning of 24 July but later that evening it still looks ‘full’ to the naked eye and now lies below left of Saturn as they rise. Look about 11pm towards the southeast and Jupiter will be above the horizon too. Next evening the Moon lies to the lower right of the giant planet.

Noctilucent clouds

Noctilucent clouds Peter Lee, Wiltshire, 21 June 2019. Equipment: Canon EOS 700D DSLR camera, Tamron SP 70-300 lens.
Noctilucent clouds imaged by Peter Lee, Wiltshire, 21 June 2019. Equipment: Canon EOS 700D DSLR camera, Tamron SP 70-300 lens.

The last week of May sees the start of Noctilucent Cloud season, so it’s well worth keeping an eye out towards the north for these ‘Night Shining’ ethereal clouds. For more info, read our guide to Noctilucent Clouds.

More conjunctions in July 2021

  •   1 July Last Quarter Moon forms shallow triangle with Iota Ceti and Neptune
  •   4 July Moon lies to right of Uranus (morning)
  • 16 July Moon forms triangle with Porrima and Spica (evening)
  • 18 July Moon lies above Alpha Librae (evening)
  • 20 July Moon lies to upper left of Antares (evening)
  • 28 July Moon lies below and a little left of Neptune (morning)
  • 31 July Last Quarter Moon lies close to Xi Ceti (morning)

Paul Money is BBC Sky at Night Magazine’s Reviews Editor and author of the annual Nightscenes guide on what to see in the night sky

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each month.

Mars Jupiter Conjunction by James Robertson, Lake District, UK. Equipment: Zwo asi120mc-s, Canon zoom lens at 18mm
Mars Jupiter Conjunction by James Robertson, Lake District, UK. Equipment: Zwo asi120mc-s, Canon zoom lens at 18mm
Moon, Venus, Jupiter and Mars Conjunction 8 Oct 2015 by Peter Louer, Tenerife. Equipment: Canon 700D 18-55mm Lens
Moon, Venus, Jupiter and Mars Conjunction 8 Oct 2015 by Peter Louer, Tenerife. Equipment: Canon 700D 18-55mm Lens
Moon, Venus, Jupiter & Mars Conjunction 10 Oct 2015 by Peter Louer, Tenerife. Equipment: Canon 700D, Samyang 10mm Lens
Moon, Venus, Jupiter & Mars Conjunction 10 Oct 2015 by Peter Louer, Tenerife. Equipment: Canon 700D, Samyang 10mm Lens
Moon & Co by Jonathan, London. Equipment: Sony
Moon & Co by Jonathan, London. Equipment: Sony
Planetary Trio Conjunction Venus Jupiter Mars by Martin Marthadinata, Surabaya, E. Java, Indonesia. Equipment: Nikon D5000, 50mm lens
Planetary Trio Conjunction Venus Jupiter Mars by Martin Marthadinata, Surabaya, E. Java, Indonesia. Equipment: Nikon D5000, 50mm lens
Venus Mars and Jupiter by John Brady, W. Lancashire, UK. Equipment: Canon Powershot SX60 IS
Venus Mars and Jupiter by John Brady, W. Lancashire, UK. Equipment: Canon Powershot SX60 IS
Jupiter, Venus, Mercury by Colin Brumfitt, Moreton Beach, Wirral, Merseyside, UK. Equipment: Sony a100, tripod.
Jupiter, Venus, Mercury by Colin Brumfitt, Moreton Beach, Wirral, Merseyside, UK. Equipment: Sony a100, tripod.
Venus, Jupiter, Moon & Mercury by Richard Sass, Cloudcroft, New Mexico USA. Equipment: Nikon D-40, 18mm lens, Tripod
Venus, Jupiter, Moon & Mercury by Richard Sass, Cloudcroft, New Mexico USA. Equipment: Nikon D-40, 18mm lens, Tripod
Jupiter & Moon by Brian.M.Johnson, Hove, UK. Equipment: Canon 50D.
Jupiter & Moon by Brian.M.Johnson, Hove, UK. Equipment: Canon 50D.
Crescent Moon & Jupiter Close Conjunction by Anthony Burley, Redditch, Worcs, UK. Equipment: Skywatcher 150P, Nikon 5100
Crescent Moon & Jupiter Close Conjunction by Anthony Burley, Redditch, Worcs, UK. Equipment: Skywatcher 150P, Nikon 5100
Crescent Moon & Jupiter Close Conjunction by Anthony Burley, Redditch, Worcs, UK. Equipment: Skywatcher 150P, Nikon 5100
Crescent Moon & Jupiter Close Conjunction by Anthony Burley, Redditch, Worcs, UK. Equipment: Skywatcher 150P, Nikon 5100
The Moon and Jupiter Meet by Steve Jarvis, Churwell, Leeds, UK. Equipment: Olympus E410, Celestron 80mm Travelscope.
The Moon and Jupiter Meet by Steve Jarvis, Churwell, Leeds, UK. Equipment: Olympus E410, Celestron 80mm Travelscope.
Christmas Conjunction: Jupiter & Moon by André Gonçalves, Vieira do Minho, Braga, Portugal. Equipment: SkyWatcher 80ED, Canon 1000D
Christmas Conjunction: Jupiter & Moon by André Gonçalves, Vieira do Minho, Braga, Portugal. Equipment: SkyWatcher 80ED, Canon 1000D
Moon and Jupiter by Humberto Cecim, Brazil. Equipment: 114/1000 Reflector Greika, Fujifilm Finepix S2800 HD
Moon and Jupiter by Humberto Cecim, Brazil. Equipment: 114/1000 Reflector Greika, Fujifilm Finepix S2800 HD
Occultation of the Moon and Jupiter by Alastair Willis, Shire of Augusta, Margaret River, Western Australia. Equipment: Nexstar 8se, Olympus FE-100.
Occultation of the Moon and Jupiter by Alastair Willis, Shire of Augusta, Margaret River, Western Australia. Equipment: Nexstar 8se, Olympus FE-100.
46 Hour Old Moon and Jupiter by Brian R Bugler, Worth Matravers, Dorset, UK. Equipment: Canon 5D mk II, 70-200 f2.8L zoom lens.
46 Hour Old Moon and Jupiter by Brian R Bugler, Worth Matravers, Dorset, UK. Equipment: Canon 5D mk II, 70-200 f2.8L zoom lens.
Moon with Jupiter by Philip Pugh, Chippenham, UK. Equipment: Nikon D3200, tripod
Moon with Jupiter by Philip Pugh, Chippenham, UK. Equipment: Nikon D3200, tripod
Moon-Jupiter Conjunction by John Bell, Haversham, Milton Keynes, UK. Equipment: Canon 5D mk2, 200mm f2.8 lens.
Moon-Jupiter Conjunction by John Bell, Haversham, Milton Keynes, UK. Equipment: Canon 5D mk2, 200mm f2.8 lens.
Conjunction of Waning Moon and Jupiter by Sarah & Simon Fisher, Bromsgrove, Worcestershire, UK. Equipment: Canon 600D, 300mm
Conjunction of Waning Moon and Jupiter by Sarah & Simon Fisher, Bromsgrove, Worcestershire, UK. Equipment: Canon 600D, 300mm
Conjunction of Jupiter and Waning Moon by Sarah & Simon Fisher, Bromsgrove, Worcestershire, UK. Equipment: Canon 600D, 300mm
Conjunction of Jupiter and Waning Moon by Sarah & Simon Fisher, Bromsgrove, Worcestershire, UK. Equipment: Canon 600D, 300mm
Moon, Jupiter and Galilean Moons by Steve Brown, Stokesley, N. Yorkshire, UK. Equipment: Canon 600D, 250mm lens, tripod.
Moon, Jupiter and Galilean Moons by Steve Brown, Stokesley, N. Yorkshire, UK. Equipment: Canon 600D, 250mm lens, tripod.
Waxing Moon & Jupiter by Sarah & Simon Fisher, Bromsgrove, Worcestershire, UK. Equipment: Canon 600D, 300mm
Waxing Moon & Jupiter by Sarah & Simon Fisher, Bromsgrove, Worcestershire, UK. Equipment: Canon 600D, 300mm
Jupiter and the Moon in Conjuction by John Foster, Plymouth, UK. Equipment: Nikon D3200, Evostar 102/1000 frac, EQ3 mount.
Jupiter and the Moon in Conjuction by John Foster, Plymouth, UK. Equipment: Nikon D3200, Evostar 102/1000 frac, EQ3 mount.
Planets, Moon and More by Alfredo Balreira, Rio Tinto, Portugal. Equipment: Canon Eos 1000D, Tripod.
Planets, Moon and More by Alfredo Balreira, Rio Tinto, Portugal. Equipment: Canon Eos 1000D, Tripod.
Conjunction over Brisbane by Teale Britstra, Brisbane, Queensland, Australia. Equipment: Canon 600D, 18-55mm lens
Conjunction over Brisbane by Teale Britstra, Brisbane, Queensland, Australia. Equipment: Canon 600D, 18-55mm lens
Venus, Jupiter and the Moon by Graham Green, Brighstone, Isle of Wight. Equipment: Canon EOS 600D, Canon EF 14mm lens, Astronomik CLS CCD filter, AstroTrac.
Venus, Jupiter and the Moon by Graham Green, Brighstone, Isle of Wight. Equipment: Canon EOS 600D, Canon EF 14mm lens, Astronomik CLS CCD filter, AstroTrac.
Sunset, Jupiter, Venus and Crescent Moon by Jenny Budden, Wimborne, UK. Equipment: Nikon D200, 18-200 lens.
Sunset, Jupiter, Venus and Crescent Moon by Jenny Budden, Wimborne, UK. Equipment: Nikon D200, 18-200 lens.
The Moon Jupiter & Venus over Tenerife by Peter Louer, Tenerife. Equipment: Canon 700d, 55mm Lens
The Moon Jupiter & Venus over Tenerife by Peter Louer, Tenerife. Equipment: Canon 700d, 55mm Lens
Moon, Venus and Jupiter Rising by Steve Brown, Stokesley, N. Yorkshire, UK. Equipment: Canon 600D, 250mm lens, tripod.
Moon, Venus and Jupiter Rising by Steve Brown, Stokesley, N. Yorkshire, UK. Equipment: Canon 600D, 250mm lens, tripod.
Jupiter - Venus conjunction and Cookham Dean Church by Roger Palframan, Cookham Dean, Berkshire, UK. Equipment: Nikon D300s, 16-85mm (~40mm).
Jupiter – Venus conjunction and Cookham Dean Church by Roger Palframan, Cookham Dean, Berkshire, UK. Equipment: Nikon D300s, 16-85mm (~40mm).
Jupiter and Venus March 2012 by George Zealey, Effingham, Surrey, UK. Equipment: Sony Alpha A390, Sony 18-75mm lens.
Jupiter and Venus March 2012 by George Zealey, Effingham, Surrey, UK. Equipment: Sony Alpha A390, Sony 18-75mm lens.
Conjunction by Mohammad Reza Ghorbanzade, Babol, Iran. Equipment: Fuji Film Finepix S4000.
Conjunction by Mohammad Reza Ghorbanzade, Babol, Iran. Equipment: Fuji Film Finepix S4000.
Dawn conjunction of Venus, Jupiter and the Pleiades by Jonathan Green, North Shore, Auckland, New Zealand. Equipment: Canon 60Da, 28-80mm Canon lens.
Dawn conjunction of Venus, Jupiter and the Pleiades by Jonathan Green, North Shore, Auckland, New Zealand. Equipment: Canon 60Da, 28-80mm Canon lens.
Jupiter/Venus by Baz Pearce, Bolton, UK. Equipment: Celestron Maksutov 127SLT, SPC900 webcam, baader ir/uv cut filter, Astro Engineering 0.6x focal reducer.
Jupiter/Venus by Baz Pearce, Bolton, UK. Equipment: Celestron Maksutov 127SLT, SPC900 webcam, baader ir/uv cut filter, Astro Engineering 0.6x focal reducer.
Venus and Jupiter Conjunction by Michael LaMonaco, United States, New Jersey. Equipment: Celestron 8SE, Advanced VX mount, Canon 60Da, Skyris 445C
Venus and Jupiter Conjunction by Michael LaMonaco, United States, New Jersey. Equipment: Celestron 8SE, Advanced VX mount, Canon 60Da, Skyris 445C
Venus and Jupiter by Allan Payeras, Paraná, Brazil. Equipment: Samsung NX1000, Samsung 20-50mm.
Venus and Jupiter by Allan Payeras, Paraná, Brazil. Equipment: Samsung NX1000, Samsung 20-50mm.
The Conjunction by John Short, Whitburn, Tyne and Wear, UK. Equipment: Canon 5Dmkii, Canon 70-300L lens
The Conjunction by John Short, Whitburn, Tyne and Wear, UK. Equipment: Canon 5Dmkii, Canon 70-300L lens
Jupiter & Venus Conjunction by Peter Louer, Tenerife. Equipment: Canon 700D, 18-55mm lens.
Jupiter & Venus Conjunction by Peter Louer, Tenerife. Equipment: Canon 700D, 18-55mm lens.
Evening Star of Venus VS Jupiter by Nazam Anuar, Johor, Malaysia. Equipment: Sony A6000.
Evening Star of Venus VS Jupiter by Nazam Anuar, Johor, Malaysia. Equipment: Sony A6000.
Mars and the Moon by Steve Brown, Stokesley, N. Yorkshire, UK. Equipment: Canon 600D.
Mars and the Moon by Steve Brown, Stokesley, N. Yorkshire, UK. Equipment: Canon 600D.