Think February is a quiet month for stargazers? Not so in 2023. This year, a planetary conjunction comes hot on the heels of the green comet, which made its closest pass to the Earth on 1 February 2023.
The conjunction of Venus and Jupiter is underway, as Venus is rapidly approaching the granddaddy of the Solar System. Stargazers across the globe have already snapped some brilliant shots, and we’ve pulled together some of our favourite Venus-Jupiter conjunction photographs from around the globe. The action will continue tonight (and for those of us in the UK, there may be the added bonus of the aurora), so there’s still time to view this heavenly meeting.
If you’re looking forward to making the most of clear nights in 2023, why not plan ahead with ourfull Moon UK calendarandastronomy for beginners guide? Or if you’d like to maximise your chance of seeing a shooting star, we’ve rounded up all the meteor showers in this handymeteor shower calendar.
What is a conjunction?
Astronomically speaking, a conjunction is when two astronomical objects appear close to each other in the sky, as seen from our view on Earth.
"In popular parlance, the term conjunction loosely describes when two or more objects appear close to one another in the night sky. There are several formal definitions of conjunction which describe when objects share the same coordinate values, but for general discussions, being close is enough to qualify the term," explains astronomer andBBC Sky At Nightpresenter Pete Lawrence.
Conjunctions are most widely associated with planets, but they can also occur with any two astronomical objects, including asteroids, moons, stars, and of course, the Sun. You might have also heard the term inferior or superior conjunction - this refers to when a planet lies between the Earth and the Sun (inferior) or when a planet is on the opposite side of the Sun to the Earth (superior).
When is the best time to see the Venus-Jupiter conjunction?
"Late February provides an opportunity to spot both Venus and Jupiter as they appear to approach one another in the sky," says Lawrence.
Earlier in the month, from the 20 February, Venus and Jupiter could be seen together after sunset above the west-southwest horizon. Measuring the distance between the two using conventional means – holding your hand at arm’s length and closing one eye – the two planets appeared about a fist-width apart, around 30 minutes after sunset. This equates to approximately 10 degrees apart. Of course, this only refers to the apparent distance from our point of view on Earth.
A thin, waxing crescent Moon joined the pair on 21 February 2023, however cloud cover somewhat scuppered our view here in the south of the UK. You may have gotten a glimpse of the Moon nestled between Venus and Jupiter the night after, but here in the south, cloud cover was frustratingly much the same. Towards the end of the month, the Moon will progress eastward, while Jupiter and Venus get closer together.
"With both planets being so bright, if you have a phone with camera functionality, why not try and grab a snapshot of the pair?" suggests Lawrence.
On 1 and 2 March, Venus and Jupiter will be less than one degree apart in the sky. That's equivalent to the width of your pinkie when held out at arm's length. When distances get this small, a degree is subdivided further into arcminutes, and there are 60 arcminutes in one degree. Venus and Jupiter will appear 39 arcminutes apart on 1 March at their closest approach, and 45 arcminutes apart the evening after on 2 March.
After that they begin to pull apart:
"Then, as quickly as they approached one another, both planets will appear to separate again. Jupiter will slowly drift into the Sun’s glare and be lost from view for a time, but Venus will continue to separate from the Sun to light up the spring evening sky, " says Lawrence.
Venus-Jupiter 2023 conjunction, a timeline of events
Here is the timeline of events for the 2023 conjunction:
- 20 February 2023:Venus and Jupiter were around 10 degrees apart, seen 30 minutes after sunset.
- 21 February 2023:The duo was joined by a thin, waxing crescent Moon.
- 26 February 2023:Keen stargazers in the UK spotted Venus and Jupiter against a rare aurora backdrop.
- 27 February 2023:Venus is moving closer to Jupiter, and both are visible to the naked eye in the constellation Pisces. Mars will also be visible adjacent to a first-quarter Moon.
- 28 February 2023:Venus is getting higher in the sky, rapidly approaching Jupiter, while Jupiter appears to keep pace with the stars.
- 1 March 2023:Venus and Jupiter are closest together, just 39 arcminutes apart.
- 2 March 2023:Venus and Jupiter remain close, just 45 arcminutes apart. Venus is now above Jupiter, appearing to ‘overtake’ the gas giant.
- 3 March 2023:Venus is moving away from Jupiter, as the altitude of the gas giant begins to decrease in the evening sky. Jupiter will sink into the Sun’s glare before reaching solar conjunction (on the opposite side of the Sun to the Earth) on 11 April 2023.
Why is the Venus-Jupiter conjunction so special?
Although we won’t see another Great Conjuntion until 2040, that is – a conjunction between the two gas giants, Jupiter and Saturn, the Venus-Jupiter conjunction this week should offer spectacular views, if the clouds cooperate.
As the two brightest planets in the night sky, they are visible to the naked eye without binoculars and are easily distinguishable even for the casual observer. (Although Mars sometimes exceeds Jupiter in terms of brightness, this is only for a short time, while the red planet is in opposition.)
The brightness of the planets is denoted by something astronomers call ‘apparent magnitude’. Simply put, the smaller the number, the brighter that object is. If the object has an apparent magnitude of less than 0, then it’sreallybright. During the conjunction of Venus and Jupiter, the apparent magnitude of each planet will determine how bright they appear relative to each other.
Venus is typically the brighter of the two planets, with anaverage apparent magnitude of around -4.2, while Jupiter has an average apparent magnitude of around -2.0. (For comparison, a full Moon has an average apparent magnitude of -12.74, and the Sun is -26.7.) This means that Venus will appear much brighter than Jupiter during the conjunction, however, they should both be discernible to the naked eye in the early evening sky.
Thanks to the relatively short orbit of Venus (225 days) coupled with Jupiter’s 12-year orbit, the pair reach conjunction roughly every 13 months.
The Evening Star
Back in the summer of 2022, Venus could be seen in the morning sky rising before the Sun, earning its nickname, the Morning Star. Thanks to its 225-day orbit around the Sun, relative to both the Sun's orbit and the Earth's own 365.25-day orbit, Venus returns to the same alignment relative to Earth a little under every 584 days.
For us, that means Venus appears in the morning sky for around 263 days (aka the Morning Star), and in the evening sky (aka the Evening Star) for around 263 days (with an additional period of around 58 days when the planet is too close to the Sun to be seen).
Venus is currently presenting as the Evening Star, remaining in the sky after the Sun has set in the late afternoon. As a result, it's one of the brightest objects in the twilight sky, and is easily distinguishable as we look towards the west.
"The planet Venus is now obvious in the post-sunset sky. A brilliant beacon, the brightest of all the planets visible from Earth. Second brightest for most of the time, is Jupiter. Mars can beat Jupiter for short periods when near opposition, but generally speaking Jupiter holds second place," explains Lawrence.
As we head towards the end of February, Venus appears to hold its relative position in the sky, fairly low on the western horizon, while the Moon moves further west.
What else can I see?
The Moon is currently in its waxing crescent phase of the lunar cycle, so the portion of the Moon illuminated by the Sun is increasing. It reaches the first quarter on 27 February, after which it enters its waxing gibbous phase before reaching full on 7 March. As the Moon progresses through the lunar cycle, it travels through the zodiac constellations, spending two to three days in each.
Mars will also be visible to the naked eye. Although now waning (losing its apparent brightness), on 27 February the Red Planet will be high in the sky in the constellation Taurus, keeping the Moon company in the early evening, before the Moon continues its westward journey. With a decent pair of binoculars or a telescope – and clear conditions – we may also be able to glimpse the greenish-blue disc that is Uranus, currently taking up residence in the constellation Aries.
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