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Moon and Gemini stars on May 10 and 11

Tonight – May 10, 2016 – and tomorrow night, the waxing crescent moon shines near the stars Castor and Pollux in the constellation Gemini the Twins. Watch for them in your western sky as darkness falls. Another bright star, Procyon, is also nearby.

Also, from the Northern Hemisphere, look southward at dusk and nightfall to see the planet Jupiter, the brightest starlike object in the evening sky. From the Southern Hemisphere, look in your northern sky. Because the waxing crescent moon isn’t particularly bright just yet, you can probably use the Jupiter and Regulus, the brightest star in the constellation Leo the Lion, to locate and see the Beehive star cluster (Messier 44), as shown on the chart below:

While the moon is still a thin crescent, use the dazzling planet Jupiter to locate the constellation Leo. An imaginary line from Jupiter through the bright star Regulus will enable you to locate the Beehive star cluster in the constellation Cancer. Binoculars transform this wispy cloud-like smudge of light into a sparkling array of stars.

While the moon is still a thin crescent, use the dazzling planet Jupiter to locate the constellation Leo. An imaginary line from Jupiter through the bright star Regulus will enable you to locate the Beehive star cluster in the constellation Cancer. Binoculars transform this wispy cloud-like smudge of light into a sparkling array of stars.

The unlit portion of a waxing moon always points in its direction of travel – eastward – in front of the backdrop stars. As Earth spins beneath the sky, though, the moon, stars and planets the stars go westward throughout the night. But over a period of days, you can notice that the moon is actually traveling eastward relative to the constellations of the Zodiac.

That eastward motion of the moon is a reflection of the moon’s true motion in orbit around Earth.

As a result of the moon’s eastward (orbital) motion, the moon will move somewhat closer to the star Regulus and the planet Jupiter by this same time tomorrow evening (May 11). It’ll finally meet up with the star Regulus on March 13 and the planet Jupiter on May 14.

As seen from the Southern Hemisphere, the moon passes between the Gemini stars and Procyon once a month, as well. People living south of the equator will see Procyon higher in the sky and the Gemini stars lower down.

Up or down is a matter of perspective, in the sky as in so much else.

To avoid ambiguity, in talking about the sky, we can say that Castor and Pollux lie north of the moon (in the direction toward the North Star), and Procyon lies south of the moon (in the direction away from the North Star).

Meanwhile, Jupiter lies east of the moon (toward the sunrise direction) as darkness falls over the next few days.

Bottom line: Tonight – May 10, 2016 – you’ll find the moon, the Gemini stars, the star Procyon in the western part of the sky.

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Bruce McClure

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