Cancer
What is Cancer?
Constellations· Late winter–spring (N) · between Gemini and Leo, Beehive Cluster. The faintest zodiac constellation. Its fame comes not from stars but from the Beehive Cluster (M44) glowing at its centre like a small patch of mist, filling the gap between Gemini and Leo.
📍 Visible from where you are right now — computed in your browser
bearing · altitude · rise time · best time tonight
Where Cancer is in your sky right now: https://nowsky.org/solar/sky?sel=con:Cancer — location and time set automatically, no login.
Stars of the figure
| Star | Magnitude |
|---|---|
| Tarf | 3.5 |
| Asellus Australis | 3.9 |
| Acubens | 4.3 |
| Asellus Borealis | 4.7 |
The 4 brightest of the 5 stars used in the figure (4 lines). Lower magnitude means brighter.
Deep-sky objects near this constellation
Constellation basics
| Season | late winter to spring evenings, February–April |
|---|---|
| Brightest star | Altarf (3.5) |
| How to find | the dim gap between Pollux and Regulus, with the hazy Beehive in the middle |
| Area rank | 31st of 88 |
Figures are representative approximations. Source: compiled from NASA and IAU public data.
Frequently asked
- When can I see Cancer?
- late winter to spring evenings, February–April.
- How do I find Cancer?
- the dim gap between Pollux and Regulus, with the hazy Beehive in the middle.
- What is the brightest star in Cancer?
- Tarf, magnitude 3.5.
- Where is Cancer in the sky right now?
- Open the sky view for your location and time and it shows the position in the sky right now.
The crab that remains in the name Tropic of Cancer
The northern tropic on a map is the Tropic of Cancer. Around the second century BC the Sun stood in Cancer at the summer solstice, so the latitude where the Sun reaches farthest north was given the crab's name. Precession has since carried the solstice point to the border of Taurus and Gemini, but the term in geography preserves the sky of two thousand years ago.
Its southern counterpart carries the goat's name for the same reason. The distance between the two tropics is twice the tilt of Earth's axis (23.4°), and because that tilt varies slowly over a 40,000-year cycle the tropics themselves creep toward the equator by about 15 metres a year. The faintest constellation of the zodiac has left its name most widely on the map of Earth.
The constellation in depth
Cancer is the giant crab Hera sent to distract Heracles as he fought the Hydra. It nipped the hero's foot, was crushed underfoot, and Hera rewarded its loyalty with a place in the sky. Faint as the figure is, the summer solstice once lay here, which is why the northern tropic is still called the Tropic of Cancer.
At the constellation's heart is the Beehive, M44, an open cluster about 600 light-years away holding around a thousand stars. The Greeks called it the Manger and saw the two flanking stars as donkeys, the Aselli, feeding from it. In 1609 Galileo turned his telescope on the mist and was the first to resolve it into stars. It is one of the closest clusters to the Sun and shares its age and motion with the Hyades, suggesting the two were born together.
Look for the empty-seeming patch between Pollux in Gemini and Regulus in Leo. On a moonless night, glancing slightly to one side reveals the Beehive as a soft smudge, and binoculars break it into dozens of stars. In the Sky view choose a March evening and switch on the deep-sky objects to see the cluster marked. Cancer has no bright stars of its own, so the cluster is often the first and only thing beginners find there — which is exactly the point.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.