Cancer is one of the 12 zodiac constellations, representing the crab. Although not the most prominent constellation in the night sky, it is significant due to its place in the zodiac and its association with ancient mythology. Cancer is relatively faint and can be challenging to spot, as it lacks bright stars.
Key Features
- Shape: Cancer is often depicted as an upside-down "Y" or a faint, irregular rectangle, symbolizing the body and claws of a crab.
- Position: It lies between Gemini to the west and Leo to the east. The constellation is situated in the Northern Hemisphere and can be found in the second quadrant (NQ2) of the sky.
- Size: Cancer covers an area of 506 square degrees, making it the 31st largest constellation in the sky.
Mythology
The mythological background of Cancer is tied to the Greek myth of Hercules. During Hercules' battle with the multi-headed Hydra, Hera, who despised Hercules, sent a crab to distract him. The crab attempted to hinder Hercules by pinching his feet, but it was crushed underfoot. To honor its efforts, Hera placed the crab among the stars, creating the constellation Cancer.
Notable Stars
- Alpha Cancri (Acubens): The brightest star in Cancer, though it is still relatively faint with a magnitude of 4.26. The name "Acubens" means "the claw" in Arabic.
- Beta Cancri (Altarf): The second brightest star, with a magnitude of 3.5, and it marks one of the crab's claws.
- Gamma Cancri (Asellus Borealis): A white star with a magnitude of 4.7, representing the northern donkey.
- Delta Cancri (Asellus Australis): Known as the southern donkey, it is slightly brighter than Gamma Cancri and hosts the famous open cluster M44 (the Beehive Cluster) near it.
Visibility
- Best Time to See: Cancer is best visible in the Northern Hemisphere from late winter to early spring, particularly in March and April.
- Latitude: It can be observed between latitudes +90° and -60°.
Tips for Observing
- Dark Skies: Due to the faintness of Cancer's stars, observing from a location with minimal light pollution is essential.
- Binoculars/Telescope: Using binoculars or a small telescope will help to identify Cancer’s key stars and the Beehive Cluster (M44).
- Star-Hopping: To locate Cancer, start from the easily visible constellations Gemini or Leo and move towards the space between them.