At around 1:45 a.m. EDT, Saturn reaches its exact opposition point for 2025.
Saturn in the southern sky during Opposition, on the night of September 20-21, 2025. The inset image, right, shows a telescopic view of the planet and its most prominent moons at 1:45 a.m. EDT. (Stellarium/Scott Sutherland)
Saturn Oppositions come around roughly once every 378 days. This is longer than an Earth year because as we travel around the Sun to catch up to Saturn again, Saturn has also spent one Earth-year moving much slower along its own orbit. So, the distance travelled by Saturn adds about 2 extra weeks (give or take a day or so) to our journey so we can align once again.
Saturn is not only in alignment with the Sun and Earth this weekend, it is also at its closest point to us, at a distance of 8.547 astronomical units or 1.278 billion kilometres. (An astronomical unit, or au, is the average distance between Earth and the Sun.)
That will put Saturn at its closest to Earth, and also its brightest in our night sky in over 15 years.
Saturn and its brightest moons through a powerful telescope during Opposition 2025. (Stellarium/Scott Sutherland)
Since Earth’s and Saturn’s orbits are not perfectly circular, the distance between the two planets changes each time they reach opposition. In fact, following a consistent 3-decade-long cycle, the two start at a minimum distance in late December, get farther apart with each subsequent opposition up to a maximum distance in late June, and then get closer together for each opposition after, until they reach the next minimum distance again in late December.
This latest cycle began on Dec 31, 2003, when Earth and Saturn reached opposition at around 1.2 billion km apart. On June 27, 2018, they were at their farthest opposition of this cycle, at a distance of just over 1.35 billion km.