| Name and Etymology | |
|---|---|
| Name | Cancer |
| Translation | Crab |
| Abbreviation | Cnc |
| Genitive | Cancri |
| Position and Location | |
|---|---|
| Right Ascension | 09h 00m 00s |
| Declination | +20 00' 00" |
| Bordering Constellations | Canis Minor Gemini Hydra Leo Leo Minor Lynx |
 Cancer, from the Uranographia of Johann Bode. |
 Cancer as depicted in Urania's Mirror, a set of constellation cards published in London c.1825. |
| Notable Features Cancer is the 31st largest constellation, not very large in size, for it encompasses an area of about 506 square degrees. Though it is small, observers between latitudes +90 and -60 degrees can see it, and it is best noticed throughout the whole month of March at 9 P.M. local time. Meteor Showers The Delta Cancrids is a minor meteor shower that starts roughly around the time of December 14 and lasts for about two months. Its association or source of the shower is unknown at this time. Stars The constellation of Cancer is relatively dim and hard to locate unless one is situated under dark skies, for the brightest star is Altarf, and it shines with a magnitude of a simple 3.5. It is also the brightest binary star and the brightest variable star in the whole constellation. Acubens is the principle star of the constellation, and DX Cancri, a variable star, is the group's nearest star. 55 Cancri is the brightest star within Cancer to possess planets. |
| Bright Star | Magnitude |
| Altarf | 3.50 |
| Asellus Australis | 3.93 |
| Iota Cancri | 4.00 |
| Acubens | 4.25 |
| Asellus Borealis | 4.65 |
Galactic Clusters There are two open, or galactic, star clusters within the fabricated boundaries of Cancer- M 44, also known as the Beehive Cluster, and M 67. The Beehive cluster is the brightest deepsky object within the constellation. It is best seen through a good pair of field glasses, although the cluster can be observed with the unaided eye within a dark, moonless sky. M 67, on the other hand, is not so grand and bright. It must be seen through a small to moderate telescope. Galaxies Even though there are numerous galaxies situated toward the direction of Cancer, most, if not all, are not even bright enough to be seen through a small telescope, with the exception of NGC 2775. This particular galaxy glows at a steady magnitude of about 11.5, and is the brightest within the constellation. The rest of the galaxies must be observed through a moderate or a more powerful scope to catch a glimpse of them. |
| Deep Sky Object | Object Type |
| Beehive Cluster | Galactic Cluster |
| M 67 | Galactic Cluster |
| NGC 2775 | Galaxy |
| NGC 2513 | Galaxy |
