Uranus and Neptune Conjunctions

About this pairing

Uranus and Neptune crawl along the longest planetary orbits, 84 and 165 years, and because Uranus only just outpaces Neptune the two take about 171 years to line up again. The most recent meeting was not a single event but a triple conjunction in 1993, when the two crossed paths three times near 19 degrees of Capricorn on the tropical zodiac, among the stars of Sagittarius, as they wove back and forth in their yearly retrograde loops.

The next conjunction is due around the year 2165, which is why the table below shows the 1993 meeting as the most recent and only that distant future date ahead. No other pairing waits so long between meetings, so the table for this pair looks unlike any other on the site: one event behind us, one far ahead, and nothing in between.

Neither planet is visible to the unaided eye at a conjunction like this: Uranus hovers near the naked-eye limit at magnitude 5.7 under a dark sky, while Neptune at magnitude 7.8 needs binoculars or a telescope. Finding the pair takes a star chart and patience, but they sit remarkably close together when they do meet. See binoculars and telescope picks.

Watching this pair

Treat this pairing as a project rather than a glance. Neither planet hands itself to you: Uranus asks for a dark sky or binoculars, Neptune insists on optics, and both need a finder chart or an app to pin down among the field stars. The reward is real, though. In the same low-power field you can hold the two most distant major planets at once and see, faintly green beside faintly blue, that they are not stars.

The 1993 meeting was a triple conjunction: as Earth overtook the slow pair, each planet's yearly retrograde loop carried them past each other three times within the year. Whoever charts the next series, around 2165, will watch the same slow dance. In the meantime the two are worth hunting on any clear night they are up, a pair of worlds most people have never seen with their own eyes.

Photographing Uranus and Neptune

This pair asks more of a camera than any other conjunction, because neither planet is bright and the picture is about proof rather than beauty. A tracking mount helps: at these magnitudes you want exposures of several seconds to bring the two out against the field stars, and a tracker keeps them as points through that time. A telephoto or a small telescope with a camera attached will frame both planets together, since at their meetings they sit remarkably close. A field of view of a degree or two holds both at once and still takes in the background stars that confirm which point is which.

The reward in a photograph is color. A well-exposed frame separates faintly green Uranus from deeper blue Neptune, the plainest evidence that these are worlds and not stars, and a wide enough field pins them among charted background stars so you can be certain which points you have caught. Because the pair meets only about every 171 years, no one gets a second attempt; the next series will not come until around 2165.

A rare meeting of near-twins

Uranus and Neptune are the solar system's two ice giants, alike in size and close in mass, and both wrapped in hydrogen, helium and the icy compounds that tint one a pale blue-green and the other a deeper blue. No other conjunction pairs two worlds so similar; every other meeting sets a large planet against a small one, or a rocky world against a gas giant. When these two line up it is the closest the sky comes to showing a matched pair, which makes their rare meetings a quiet curiosity as much as a spectacle.

Set against a human lifetime, this pairing is essentially a single event: whoever observed the 1993 meeting will not see another, and the next falls around 2165. That rarity is the whole appeal, and it places the pair at the far end of the sky's rhythms, well beyond the twenty-year beat of the great conjunction. You can see where it sits among the other cycles on the Cycles by Length page.

There is a striking footnote to the 1993 meeting: it was almost certainly the first Uranus-Neptune conjunction anyone watched knowing both partners were planets. The previous meeting fell around 1821, and Neptune was not found until 1846, so at every earlier conjunction one of the two was still unknown to science; Uranus itself was only recognized as a planet in 1781. That makes this the youngest of the great planetary rhythms in human awareness, a cycle we have knowingly observed exactly once, with the next chance not due until around 2165.