Tonight – May 1, 2017 – 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, shines on the other side of the moon.
Also, look eastward at dusk and nightfall to see the planet Jupiter, the brightest starlike object in the evening sky. The star in Jupiter’s vicinity is Spica, the brightest star in the constellation Virgo the Maiden.
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 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 2). It’ll finally partner up up with the star Regulus on the nights of May 3 and 4 and the planet Jupiter on the night of May 7.
As seen from the Southern Hemisphere, the moon passes between the Gemini stars and Procyon once a month, just as in the Northern Hemisphere. However, 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 1, 2017 – you’ll find the moon, the Gemini stars, the star Procyon in the western part of the sky.
Bruce McClure has served as lead writer for EarthSky's popular Tonight pages since 2004. He's a sundial aficionado, whose love for the heavens has taken him to Lake Titicaca in Bolivia and sailing in the North Atlantic, where he earned his celestial navigation certificate through the School of Ocean Sailing and Navigation. He also writes and hosts public astronomy programs and planetarium programs in and around his home in upstate New York.