Jupiter will make its closest approach to Earth in 59 years on Monday, September 26, offering a treat for sky watchers that evening.
Also, Jupiter will be at opposition, meaning it will rise in the eastern sky as the sun sets in the west, making the largest planet in our solar system particularly visible in the evening sky.
“Beyond the Moon, it should be one of the (if not the) brightest objects in the night sky,” Nasa Marshall Space Flight Center research astrophysicist Adam Kobelski said in a statement.
Earth and Jupiter follow elliptical, rather than circular, orbits, and the distance they pass each other varies over time. On Monday, Jupiter will come within 367 million miles of Earth, compared to the 600 million miles that separate the two worlds when Jupiter is at its furthest point along its path from Earth.
Although Jupiter comes into opposition once every 13 months, the last time Jupiter was this close to Earth was in 1963, according to a Nasa blog. Jupiter passing so close to Earth while in opposition is rare.
Those hoping to catch bright and relatively nearby Jupiter can simply look to the eastern horizon around sunset in the days leading up to September 26, the date itself and the days following, all of which should allow seeing the planet with the naked eye.
However, the close approach and opposition will provide even more striking views of Jupiter for those with access to telescopes or other optical equipment. You don’t need much magnification for Jupiter and any of its more than 50 moons to put on a good show.
“With good binoculars, the band (at least the central band) and three or four of the Galilean satellites (moons) should be visible,” Dr Kobelski continued in his statement. “It is important to remember that Galileo observed these moons with 17th century optics.”
The Galilean moons are Jupiter’s largest natural satellites, Io, Europa, Ganymede and Callisto. Nasa’s Europa Clipper mission could start on its way to clean the icy moon, which scientists believe has a global ocean beneath its surface, as early as October 20204.
Those who want to take an even closer look should consider a telescope at least 4 inches or larger, according to Dr. Kobelski, and possibly green and blue filters; these will enhance the visibility of Jupiter’s Great Red Spot and the ties to the great gas giant planet’s cloud layer.
“The outlook should be great for a few days before and after September 26,” Dr Kobelski said. “So take advantage of the good weather either side of this date to take in the sight.”