Solar System Phenomena — Saturn in 2021

The path of Saturn against the background stars in 2021

The upper chart shows the path of Saturn across the background stars over the course of the year. Stars to magnitude +8.5 are shown. The white circles represent the planet on the first day of the month and are scaled according to apparent magnitude. The faint paths before the first circle and after the last circle represent the planet's positions in December of last year and January of next. In general, the planet moves from right to left except when it's in retrograde and proceding in the opposite direction.

The lower chart shows how the appearance of Saturn changes over the year. Below each image is listed the date, the apparent magnitude, the apparent diameter of the disk (in arc-seconds), the geocentric distance (in au) and the opening angle of the rings. Note that the tilt of Saturn's rings varies subtly throughout the year.

The ringed planet resides in the constellation Capricornus the entire year. It is at conjunction near the end of January, rendering its close encounters with the two inferior planets, Mercury and Venus unobservable in January and February. It emerges in the dawn sky late in February and is most easily spotted from southern latitudes where it rises earlier and sets later. The first-magnitude object nears the fourth-magnitude star θ Capricorni near the end of May, about the time it enters into retrograde motion. Opposition occurs in August when the planet is visible all night. After this, Saturn is primarily an evening sky object. The rings are at their most open (20.9°) at the beginning of the year; they close to a minimum of 16.7° in May before opening again. The next ring plane crossing is in 2025 so the tilt of the rings will continue to decrease year on year until that date.

01 Januarymaximum declination south
maximum ring opening: 20.9°
10 Januaryplanetary conjunction: 1.6° north of Mercury
24 Januaryconjunction
06 Februaryplanetary conjunction: 0.4° north of Venus
03 Maywest quadrature
18 Maymaximum declination north
20 Mayminimum ring opening: 16.7°
23 Maystationary point in right ascension: direct → retrograde
02 Augustopposition: magnitude +0.2, apparent diameter 18.7 arc-seconds
11 Octoberlocal maximum ring opening: 19.4°
stationary point in right ascension: retrograde → direct
30 Octobereast quadrature
31 Decemberlocal minimum ring opening: 17.6°
The tilt of Saturn's rings in 2021


The dates, times and circumstances of all planetary and lunar phenomena were calculated from the JPL DE406 solar system ephemeris using the same rigorous methods that are employed in the compilation of publications such as The Astronomical Almanac.