Cancer constellation
Latin Cancer, genitive Cancri, abbreviation Cnc
North up, east to the left, as you see the sky. The lines are a common figure; the stars are from the catalogue.
The myth
The crab that Hera sent when Heracles fought the Hydra; Heracles crushed it, and Hera set it in the sky. The faintest constellation of the zodiac. At its centre lies the Beehive, a star cluster that shows as a faint patch on dark nights. The sun once stood here at the June solstice: hence the Tropic of Cancer.
When can Cancer be seen?
It stands highest around 10 pm in February. It can be seen from everywhere north of 62°S, and it never sets north of 81°N.
The brightest stars
| Star | Designation | Magnitude | Colour |
|---|---|---|---|
| Tarf | β Cnc | 3.52 | reddish |
| Asellus Australis | δ Cnc | 3.94 | orange |
| Zubanah | ι Cnc | 4.02 | orange |
| Acubens | α Cnc | 4.25 | white |
| Asellus Borealis | γ Cnc | 4.66 | white |
The smaller the number, the brighter: below 1 are the brightest stars of the sky, 4 is hard to see under a city sky. Greek letters after Johann Bayer (1603).
Constellation and zodiac sign
The constellation Cancer and the zodiac sign of the same name are not the same. The signs divide the Sun's path into twelve equal parts of 30 degrees, counted from the vernal equinox; the constellations differ in size, and because the Earth's axis slowly wobbles, they now lie almost one sign further on.