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More Moon and Saturn

May 13, 2017

Like bright traffic lights, two solar system objects point the way to an astronomical intersection tonight. It’s the spot where the Sun’s path across the sky meets the galactic equator.

The Moon and the planet Saturn climb into good view by midnight or a little later. Saturn looks like a bright star quite close to the right of the Moon. The astronomical intersection is just below them.

The Sun’s path is known as the ecliptic. The Moon and planets all stay close to that path. Tonight, in fact, Saturn is only about one degree above the ecliptic — less than the width of your finger held at arm’s length. So is the even brighter planet Jupiter, which is high in the south-southwest as Saturn and the Moon climb into view. Connecting the two planets lets you follow the ecliptic across the sky.

The galactic equator is a bit tougher to follow. It outlines the plane of our home galaxy, the Milky Way. It’s easiest to view under a dark sky, when there’s no Moon around. It splits the hazy band of light known as the Milky Way.

From bright cities and suburbs, though, you have to rely on bright stars to track the equator. It stretches to the upper left of the Moon and Saturn, then runs parallel to the body of Cygnus, the swan, and through W-shaped Cassiopeia, low in the north-northeast.

The galactic equator climbs higher in the sky as the night goes on. And it’ll be higher during the evening hours of summer — the hazy outline of our own galactic home.


Script by Damond Benningfield

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