Moon and faint Cancer on March 17

Tonight – March 17, 2019 – the bright waxing gibbous moon shines in front of Cancer the Crab, the faintest constellation of the zodiac. Although the moon marks Cancer’s place in the sky on this night, the moonlit glare will make Cancer tough to see.

Star chart showing stars and clusters.

The constellation Cancer via the International Astronomical Union (IAU). On a dark night, look for the Beehive star cluster (M44) to make a triangle with either bright Gemini star – Castor or Pollux – and the bright star Procyon.

However, you shouldn’t have much trouble spotting some bright stars on either side of Cancer, along the zodiac. The Gemini stars, Castor and Pollux, lie to the west of tonight’s moon whereas the star Regulus, the brightest in the constellation Leo the Lion, shines to the east of tonight’s moon.

As the Earth spins beneath the heavens throughout the night, going from west to east, the moon, Cancer, the Gemini stars and Regulus will appear to move westward across the sky.

The moon will set in the west in the wee hours before sunrise March 18.

Diagram of constellation Cancer with location of Beehive cluster marked.

There’s a faint star cluster in Cancer, called the Beehive. In a dark sky, once the moon moves away, you can glimpse it with the eye alone.

Bottom line: The bright waxing gibbous moon shines in front of Cancer the Crab, the faintest constellation of the zodiac, on March 17, 2019.

Bruce McClure