WAUKESHA, WI — The ringed planet appears its biggest and brightest for the year January 27. The evening of the 27th, the ringed planet lies opposite the Sun in our sky, a configuration astronomers call opposition.
This event also marks Saturn’s closest approach to Earth in 2006 — 755 million miles (1.2 billion kilometers) separate the two worlds then. At Saturn’s opposition, a person looking down at the solar system from above would observe the Sun, Earth, and Saturn in a straight line. People interested in seeing Saturn should have little trouble finding it high in the east during mid-evening and high in the south around midnight, shining brighter than any other star in the sky except for Sirius.
When and where in the sky? On January 27, a waning crescent sets at 3:26 p.m., sunset occurs at 5:59 p.m., and twilight ends at 6:47 p.m. Eastern Standard Time (EST). Saturn rises east-northeast in Cancer the Crab after sunset and is visible until sunrise. Find it near the edge of Cancer’s famed Beehive Cluster (M44). Binoculars will resolve this misty patch into 15 stars spread across 1° (for reference, the Full Moon appears 1/2° wide).
Saturn could hold 9.5 Earths side by side across its face. It is the second-largest planet in the solar system and has a diameter of 74,900 miles (120,500 km).
Saturn takes 29.5 Earth-years to orbit the Sun.
Saturn will reach its next farthest point from the Sun in 2018 and its next closest pass to the Sun in 2032
Saturn’s rings facts
Earth crosses the plane of Saturn’s rings in September 2009, when they will appear edge-on.
The main rings cover an area just over 15 billion square miles (40 billion square km), or 80 times Earth’s total surface area.
The rings span 174,000 miles (280,000 km), or about 73 percent of the distance separating Earth and the Moon.
It’s little wonder the rings vanish when they’re seen edge-on to Earth — they are less than 100 feet (30 meters) thick.
The total amount of material in the rings is surprisingly small: about the same mass as Saturn’s moon Mimas (120 miles, or 195 km, across).
In 1676, Giovanni Domenico Cassini (1625-1712) observed a gap in the rings known today as the Cassini Division. It’s caused by the gravity of the saturnian moon Mimas. Other, smaller gaps are associated with different saturnian moons.
In 1858, physicist James Clerk Maxwell (1831-1879) proved the rings are made of billions of particles orbiting independently.
Also in the sky:
January 27: The same evening as Saturn’s opposition, the Moon passes 12° south of Venus at 7 p.m. EST
January 29: a New Moon occurs at 9:15 a.m. EST
January 30: The Moon is at perigee, its closest point to Earth, 222,313 miles (357,778 km) away
January 31: The Moon passes 1.7° south of Uranus
Until the end of January, Mars can be seen high in the southeast. As January draws to a close, the Red Planet lies west of the Pleiades star cluster.