Jupiter is closer to the Earth than it has been since 1963, meaning the solar system's largest planet will be exceptionally bright in the sky tonight.
Every 13 months, the planet reaches "opposition," when its orbit lines up so it is on the opposite side of Earth from the sun. When this happens, Jupiter rises in the east just as the sun sets in the west, making it appear larger and brighter than at any other time of year.
This opposition is occurring a little closer than normal due to variances in both planets' orbits, said John Whitmer, an astronomy professor at Spokane Falls Community College.
Tonight, Jupiter will rise in the east at about 7 p.m. and arc across the sky before setting around 7 a.m. in the west. "Look low in the southeast just after sunset and it will be the brightest star in the sky," Whitmer said.
The best time to view the planet with a telescope is at midnight, when it will be south in the sky, he said. Jupiter's four largest moons — Calisto, Europa, Ganymede and Io — should be visible with a pair of binoculars. The Galilean moons "line up nicely" and "move fairly quickly" throughout the night.
With mostly clear skies forecast by the National Weather Service, tonight's view should be unobstructed. But if not, the good views will continue for the next month or so, Whitmer said. The brightness does not noticeably change from night to night.
"It has been pretty bright for the last couple months," he said. "It's not like it will be that much brighter than the night before."
Jupiter is now approximately 367 million miles in distance from Earth, about the same distance it was in 1963, according to NASA. The gas giant reaches about 600 million miles away from Earth at its farthest point.
Whitmer said it is also a good time to observe Saturn, which is approaching its own opposition.
