Location and Appearance
The most inconspicuous of the zodiac constellations, Cancer is composed of only a few faint stars. It is located between Pollux in Gemini and Regulus in Leo. Its most prominent feature is the open star cluster called the Beehive or Praesepe, Latin for “The Manger”.
Cancer’s Former Relation to the Summer Solstice
This sign was named over 2500 years ago when the sun approached these stars at the time of the summer solstice. Solstice means “sun stand still “, describing how the apparent motion of the sun appears to slow and stop at this time of year. During these days, the sun appears to move to the side from one noon to the next, much like the sideways motion of a crab. Most of the year, the change is more of a rise or fall on successive noons. The Tropic of Cancer marks the northernmost latitude at which the sun is seen overhead at noon, 23.5° north of the Equator. This occurs on the summer solstice. The sun was in Cancer on the solstice at the time the Tropic was named, but precession has moved this position.
Mythology of Cancer
The ancients of the Middle East saw these stars as a crab, tortoise, or beetle – all relatively slow movers. In Egypt, they were specifically seen as a Scarab Beetle, a sign of immortality, still seen today on jewelry. Greek legend tells how Hercules crushed the crab after it bit him as the Hydra attacked. The goddess Hera, who hated the hero, placed the animals in the heavens as a reward. In China, these stars were part of a large constellation called “The Red Bird”. In Tibet, a frog was found here. One of its legs stretches to Pollux in Gemini.
Mythology of the Beehive Cluster
Many other cultures focused only on the Beehive cluster. Collectively, its brightness is greater than any of the 6 noticeable stars. Medieval Christians saw the Christ child’s manger here. Two stars to the left were called ‘the donkeys”. The Hindus referred to the cluster as a flower. The Tewa Pueblo Indians called it a headdress. In ancient Iraq this cluster was “the gate of men”, the entryway of the souls into the human body. Conversely, in China, just the opposite was seen: the exhalation of piled-up corpses.
Cancer to the Greeks and Romans
The ancient Greeks used this as a weather forecaster. The slightest moisture hid its light without obscuring nearby stars. This often indicated rain within 24 hours. The Greek physician Hippocrates saw a resemblance between a tumor in a patient and the shape of a crab. He called this carcinoma, Greek for crab and tumor. The Romans later translated this to cancer, the disease. Understandably, those born under this sign are not called “cancers”. Instead they are called “moon children”, from an ancient tradition that the moon was located among these stars at the creation, and therefore reigned over them.
Astronomy in Cancer
The Beehive cluster, or Praesepe, is one of the nearest star clusters. It is also known as M44, the 44th object in Messier’s famous catalog of comet-like objects. It is about 3 times the size of the full moon and is composed mostly of orange and yellow stars, older than the Pleiades. Galileo saw this cluster through his simple telescope over 400 years ago. He saw a multitude of stars where before only a fuzzy patch was seen. This and other telescopic discoveries fomented a revolution in cosmological thinking.
For astrologers, the sun ruled here for 32 days from June 21 to July 22. In modern times, astronomers see the sun here from July 21 to August 10, only 21 days. It has an area of 506 square degrees, 31st among the constellations, almost as big as starry Orion. Only 6 stars and the cluster are brighter than 4.8 magnitude. All are easily obscured by the slightest light pollution or moonlight. Cancer is best seen 10 pm daylight time in mid-March, but can be found from mid-December to mid-June.