Before tonight's fireworks, look up for the night sky's pre-show
If fireworks are on your agenda tonight, the night sky can provide the pre-show.
As the sun sets around 8:30 p.m. tonight, look to the south. Jupiter, the second brightest object in the sky, will be hard to miss. Even a cheap discount store telescope will show Jupiter's four largest moons (there are 65 others).
Around 9 p.m., the moons will be arranged with Io (Jupiter's inner most moon) then Europa so close to each other on the left they’ll be hard to tell apart, then Ganymede and Callisto further to the right.
Look again between midnight and 2 a.m., and Europa will orbit behind Jupiter. These moons move fast, as Europa circles Jupiter every 85 hours.
Look right to the west for the brightest object, Venus. A small telescope will show that a little more than half of Venus is illuminated this week. Venus sets at 11 p.m. but will likely dip below the trees and buildings for you well before that.
Those two bright planets are all you’ll see during dusk, or more accurately, civil twilight, the period between sunset and when the geometric center of the sun is 6 degrees below the horizon. Next comes nautical twilight shortly after 9 p.m. when more stars appear and planets come into view.
Around 9 p.m., look to the south east for Saturn. Saturn will be right above the lid of the teapot shape of stars in Sagittarius.
A moderate telescope reveals Saturn’s rings, which look their best right now. By 2024, Saturn’s orbit will bring it to a point where the rings will disappear from view as we view them edge on, reappearing over the next ten years.
Jupiter and Venus should be easily viewable from any of the areas fireworks shows, but Saturn may be a bit more of a challenge to see. If your plans this evening take you to a more rural setting, an asteroid may be within view.
Look just up and to the right of Saturn for main belt asteroid 4 Vesta. Vesta is about the size of Ohio, among the largest objects in the asteroid belt. In 2011, NASA’s Dawn spacecraft orbited Vesta, studying the early formation of the solar system. Vesta’s orbit is at its closest to Earth, bringing it into view without a telescope.
You may have seen some claims in social media and the British tabloids suggesting Vesta is a threat. It is big -- about the size of Ohio -- and so large that it's considered a minor planet. But Vesta’s orbit keeps it safely away from Earth.
Vesta is a comfortable 109 million miles away. Venus, Mars and the Sun are closer.
Tony Rice is a volunteer in the NASA/JPL Solar System Ambassador program and software engineer at Cisco Systems. You can follow him on Twitter @rtphokie.
