Astronomy Magazine News Release

2008 July 2

(JUL 2) WAUKESHA, Wis. - Jupiter, largest of the planets, reaches maximum brilliance July 9. On that date, the giant planet will lie at a point astronomers call opposition. As viewed from Earth, Jupiter is directly opposite the Sun. On the 9th, Jupiter will rise at sunset, set at sunrise, and be visible in the sky all night.

July’s opposition also is when the planet lies closest to Earth, so Jupiter will shine brightest and appear largest. Furthermore, opposition places a planet due south at local midnight. Looking south, we view the planet through the least amount of Earth’s atmosphere. The higher a celestial object, the less air we’re looking through and the better the view.

“Jupiter is a great target for beginning observers,” says Astronomy contributing editor Mike Reynolds. “You’ll spot its two largest cloud belts, and you can watch the bright moons change positions from night to night.” Jupiter’s four largest satellites, discovered by Galileo in 1610, are easy to see even through small telescopes.

This year, Jupiter rises in the southeast. It lies at the eastern end of the southern zodiac constellation Sagittarius the Archer. Unfortunately, that position means Jupiter won’t appear high in the sky. From latitude 40° north, the planet’s highest altitude will be only 28° above the southern horizon. This altitude goes up 1° for every degree south you travel.

Jupiter is easy to spot. It shines at magnitude –2.7. This means it appears more than 8 times as bright as the brightest star currently in the night sky, Arcturus. Of all “starlike” objects you can spot in July, only Venus, which appears low in the west right after sunset, is brighter. On July 17, the nearly Full Moon passes 3degamp; south of Jupiter.

Copyright © 2008, Brian Webb. All rights reserved.