Astronomy Essentials

Inferior conjunction of Venus August 13, 2023

Composite of Venus phases, February 2023 to August 2023.
View at EarthSky Community Photos. | Vedant Pandey wrote: “I am Vedant Pandey, a 17-year-old amateur astrophotographer from Varanasi, Uttar Pradesh, India. I photographed Venus since it appeared in the evening sky in February, 2023. And here are the phases of Venus, from waxing gibbous in February to its crescent phase in August, as seen by my telescope.” Wow! Thank you, Vedant! Venus will reach inferior conjunction – coming between us and the sun – this Sunday, August 13. And this sequence shows how much the planet’s appearance has changed from our earthly perspective, as both Earth and Venus have moved in orbit throughout 2023. Thank you, Vedant! 

Venus in inferior conjunction

Venus travels one step inward from Earth in orbit around the sun. Its orbit is smaller than Earth’s. It has less distance to cover. And it moves faster in orbit (about 35 km/s in contrast to about 30 km/s for Earth). Yet – because Earth travels fast, too – Venus manages to gain a lap on us, going between us and the sun, only about every 19.5 months. And, at such times, earthly astronomers say Venus is in inferior conjunction with the sun. Venus comes to inferior conjunction in 2023 at 11 UTC (6 a.m. CDT) on Sunday, August 13, 2023.

Will you see Venus on the day of inferior conjunction? It’s not likely, unless you’re an extremely careful and experienced telescopic and/or photographic observer. After all, on the day of inferior conjunction, Venus will be crossing the sky with the sun during the day.

More about when we’ll see Venus next, below.

So, in a casual way, we say Venus goes between us and the sun on August 13, 2023. But it doesn’t go directly between. If it did, there’d be a transit of Venus. Venus – our closest planetary neighbor and the brightest planet in our sky – passes between the Earth and the sun about every 19 months (1.6 years). So inferior conjunction for Venus happens that often.

But transits of Venus are rare. And they happen in pairs.The last transits of Venus were on June 5-6, 2012 … and June 8, 2004. The previous pair of transits were in December 1874 and December 1882. The next transits of Venus will take place on December 10-11, 2117, and December 8, 2125.

A very thin crescent Venus, like a featureless, slightly fuzzy crescent moon.
View at EarthSky Community Photos. | In early August 2023, Venus was going, going … almost gone between us and the sun. Astronomers call this an inferior conjunction of Venus. And Roberto Ortu in Cabras, Sardinia, Italy caught Venus through a telescope on August 3. So its lighted face is turned mostly away from us now, and this planet – the brightest one seen from Earth – appears through telescopes as a waning crescent. It’s getting thinner and thinner each day. Thank you for this marvelous photo, Roberto!

The 2023 inferior conjunction of Venus

In 2023 – moving in a retrograde manner through the constellation Cancer the Crab – Venus will pass south of the sun in our sky at the moment of inferior conjunction, at a comfortable distance of 7.7 degrees.

At the moment of inferior conjunction, Venus will officially shift from the evening to the morning sky for all observers on Earth.

Diagram with sun, Earth, and 8 positions of Venus around its orbit showing its phases.
View larger. | As seen from the north side of the solar system, Venus (and all the planets) travel counterclockwise around the sun. Inferior conjunction – when Venus sweeps between the sun and Earth – happened last on January 8-9, 2022. It happens again on August 13, 2023. Illustration by John Jardine Goss/ EarthSky.

When will you next see Venus?

So, when you can expect to see Venus come back to the morning sky? Around August 21, 2023, look east about 30 minutes before sunrise. Since Venus is the brightest planet, you’ll be able to spot it low in the east, near the sunrise point, not long before the sun comes up. Venus will surprise you with its brightness so low in the sky! In fact, by the beginning of September, Venus will be heading for another greatest brilliancy around September 19.

Cycles of Venus

The 1.6-year period – after which the position of Venus relative to the sun repeats, as seen from Earth – is called its synodic period.

Notice that five synodic periods of Venus add up to eight years (just 2 1/2 days short). And so we have a cycle: inferior conjunctions of Venus that are eight years apart happen at the same time of year, in the same part of the sky, with Venus at a similar angular distance from the sun, that is, the same apparent distance from the sun on the sky’s dome. Over time, this 2 1/2 day variance will accumulate, so that the conjunctions “jump” into the previous month.

So inferior conjunctions of Venus strongly resemble each other on an 8-year cycle.

June transits of Venus

The June 3, 2020, passage of Venus between us and the sun was quite dramatic. Venus appeared in our sky within “touching distance” of our star. Venus missed the solar disk in 2020 by only a quarter of a degree.

So, in 2020, Venus fell short of transiting, or crossing, the solar disk as it had done eight years earlier, on June 5, 2012 (and also eight years before that, on June 8, 2004).

With the conjunctions of 2004 and 2012 resulting in transits, and the one in 2020 resulting in a near-miss, one could correctly conclude that the angular distance from the sun during these (currently) June series of inferior conjunctions is slowly but steadily increasing. And so they are. The June-May inferior conjunctions of Venus will not result in any more transits for many centuries.

Bar graph with many numbered yellow bars increasing regularly in height from left to right, with dates beneath.
Angular distances from Venus to the ecliptic (sun’s path in our sky) during June-May series of inferior conjunctions of Venus between years 1996 and 2132. The distances are shown in degrees. Bars with a “T” mark the transits of Venus in 2004 and 2012. You can see that, in the June-May series, the angular distance between Venus and the sun is increasing. Hence there will be no Venus transits to expect in June or May for centuries to come. Image via Milan B.

January transits of Venus

The last inferior conjunction on January 8-9, 2022, did not carry the drama of its predecessor in June 2020.

During the previous January inferior conjunction on January 10, 2014, Venus was around 1/3 of a degree farther from the sun than it was at the January 8-9, 2022, event. The next January conjunction, in 2030, will fall even closer than 2022, at just 4.5 degrees. So one might assume that this January series is slowly inching (in astronomical terms) towards the sun.

And that would be a correct assumption. Venus is currently getting closer and closer to the sun on the sky’s dome at the January inferior conjunctions.

What’s more, as the conjunction of 2022 fell on the 8th day of January, the 2 1/2 day shift will cause this January series to shift into December relatively soon, in 2045. From that moment, the now-December series will result in closer and closer approaches to the sun in the second half of the century and in the early 22nd century. The angular distance with the sun at the December inferior conjunction series will have decreased so much that it will bring us another pair of transits in years 2117 and 2125.

Some children alive today will likely live to see the Venus transits of the early 22nd century.

Bar graph with many dated blue bars, high at the left and descending to low at the right.
Angular distances from Venus to the ecliptic (sun’s path in our sky) during the January-December series of inferior conjunctions of Venus between years 1998 and 2133. The distances are shown in degrees. The bar marked “IC” indicates the last inferior conjunction on January 8-9, 2022. “T” bars mark upcoming transits of Venus in 2117 and 2125. Image via Milan B.

For experts, seeing Venus at inferior conjunction

Please do not attempt to observe Venus near the sun unless you’re an experienced sun observer.

Keen observers – depending on your location – might be able to see Venus through a telescope at – or near inferior conjunction – when it passes over 7 degrees south of the sun on August 13, 2023. It’ll shine at -4.1 magnitude. And it’ll be a razor-thin crescent, 0.87% illuminated and 57.8 arcseconds across.

To see a precise view from your location, try Stellarium Online.

Bottom line: Venus comes to inferior conjunction – passing between Earth and sun – in 2023 at 11 UTC on August 13 (6 a.m. CDT).

Read more from Guy Ottewell: The 5 ‘petals’ of Venus and its 8-year cycle

August 11, 2023
Astronomy Essentials

Like what you read?
Subscribe and receive daily news delivered to your inbox.

Your email address will only be used for EarthSky content. Privacy Policy
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.

More from 

Milan B

View All
No items found.