Celestial Events SA
Cancer - Constellation of the Month
With South Africa's national lockdown in full effect, why not use the time to learn more about the dazzling constellations overhead! This month we feature the zodiacal constellation of Cancer.
Look back over our series for more information on the following constellations:
Cancer can be found between Gemini and Leo in the in the northern half of the sky. It is the faintest of the zodiacal constellations and is sometimes hard to spot in more light polluted skies. It is easiest found by looking for the diffuse haze of its most famous deep sky object, the Butterfly Cluster.
THE MYTHOLOGY OF CANCER
Cancer is the smallest and faintest of the Zodiac signs. Not much mythology exists but accounts suggest that Cancer represents a crab sent by Zeus’s wife, Hera, to distract Hercules from his 2nd labour of slaying the Lernaean Hydra.
The Hydra was a monster with many heads that regrew when decapitated, as well as poisonous breath and blood. The crab nipped at Hercules’s feet but was crushed by his sandal. Hercules defeated the Hydra by systematically removing its heads and cauterizing the wounds with a torch to prevent them from growing back. Hera honoured the (unsuccessful) role of the crab by immortalising it in the sky as Cancer.
In the time of the Ancient Greeks, the summer solstice, the highest point of the Sun in its annual journey, coincided with the Sun being in Cancer and thus this line became known as the Tropic of Cancer. Since then, the wobble of Earth’s orbit (Precession) has seen the solstice move through Gemini and is currently in Taurus.
DEEP SKY OBJECTS IN CANCER
Messier 44, also known as the Beehive Cluster, is one of the largest Open Clusters in the Sky. It shares motion with the Hyades cluster in Taurus, suggesting the 2 groups of stars may have come from the same molecular cloud.
The Beehive Cluster manifests as a cloudy spot between Gemini and Leo and is best viewed with binoculars. Within the cluster, over 1000 young stars are embarking on the stellar journeys.
Its alternative name is Praesepe, meaning ‘manger;. It is situated between 2 stars in Cancer named the ‘Northern’ and ‘Southern Donkey Colt’ and represents the store of hay for these celestial asses.