Moon and faint Cancer the Crab on February 24, 2021


On February 24, 2021, 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.

But notice the stars to either side of the moon on February 24. Then, find these stars again when the moon has moved away. That way – if you have a dark sky – you can find Cancer and its hidden gem, the Beehive star cluster.

A few 2021 lunar calendars left! Order yours before they’re gone.

Star chart showing stars in black on white and clusters in yellow.

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 (both upper right) – and the bright star Procyon in Canis Major (lower right).

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 all appear to move westward across the sky.

The moon will set in the west in the wee hours before sunrise February 25.

Read more: Cancer? Here’s your constellation

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. Read more about the Beehive.

Bottom line: The bright waxing gibbous moon shines in front of Cancer the Crab, the faintest constellation of the zodiac, on February 24, 2021. Notice Castor and Pollux to the west of the moon, and Regulus to the east of the moon. Then come back when the moon is gone to find Cancer between these stars.

Bruce McClure