Cancer, the Crab, is the faintest constellation of the zodiac, a dim figure between Gemini and Leo whose treasure is the Beehive, a cluster seen by eye.
At a glance
| stars in the figure | 5 |
|---|---|
| nearest star of the figure | Asellus Australis, 131 light-years (40 pc) |
| farthest star of the figure | Iota Cancri, 331 light-years (102 pc) |
| depth | the farthest is 2.5 × farther than the nearest |
| zodiac | ♋ the ecliptic runs through it |
Read off the piece’s own catalogue, the same values it draws with.
About Cancer
Cancer is the crab of Greek myth sent by Hera to harass Heracles, and crushed underfoot. Its stars are faint: Acubens, at a claw, Tarf, Iota Cancri and the two Aselli, the donkeys, which flank the Beehive Cluster as if feeding at a manger. The Beehive, also called Praesepe, is a misty patch to the eye that the first telescopes showed to be a swarm of stars.
In antiquity the Sun stood in Cancer at the June solstice, which is why the Tropic of Cancer carries its name; the wobble of Earth’s axis has since moved that point into neighbouring constellations. The ecliptic runs through the figure, and Cancer is best seen on northern late winter and spring evenings, away from city lights.
What you see in the piece
Flown out to, the faint crab spreads only a little, from Asellus Australis to Iota Cancri, and the Beehive, behind them, stays together as a real cluster.
Questions
Why is it called the Tropic of Cancer?
In antiquity the Sun lay in Cancer at the June solstice, when it stands overhead at that line of latitude; the name stayed after precession moved the solstice point.
How far away are the stars of Cancer?
They range from Asellus Australis, 131 light-years (40 pc), to Iota Cancri, 331 light-years (102 pc): the farthest is 2.5 × farther than the nearest.