Arc to Arcturus, spike to Spica

Arcturus: Chart showing the Big Dipper at top left. A red line originating at the bottom of the Big Dipper points to Acturus, at the middle bottom. Spica is at the bottom right.
The star Arcturus is easy to identify. Use the Big Dipper to follow the arc to Arcturus and drive a spike to Spica.

Follow the arc to Arcturus and drive a spike (or speed on) to Spica.

First locate the Big Dipper in the northeastern sky. Draw an imaginary line following the curve in the Dipper’s handle until you come to a bright orange star. This star is Arcturus in the constellation Boötes the Herdsman.

Arcturus is a giant star at an estimated distance of 37 light-years from Earth. It’s special because it’s not moving with the general stream of stars in the flat disk of the Milky Way galaxy. Instead, Arcturus is cutting perpendicularly through the galaxy’s disk at a tremendous rate of speed … some 100 miles (160 km) per second. Millions of years from now this star will be lost from the view of any future inhabitants of Earth, or at least those who are earthbound and looking with the eye alone.

Now drive a spike or, as some say, speed on to Spica in the constellation Virgo the Maiden.

Spica, in the constellation Virgo, looks like one star, but this single point of light is really a multiple star system – with two hot stars orbiting very close together – located at an estimated distance of 262 light-years away from Earth.

Sky chart with arrow going from 2 stars at the top of Corvus to Spica.
Here’s another way to verify that you’re looking at Spica, the brightest star in the constellation Virgo.

Bottom line: Follow the arc to Arcturus and drive a spike to Spica.

Big and Little Dippers: Noticeable in northern sky

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May 8, 2021

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Deborah Byrd

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