If you know that the zodiacal constellations are all on the ecliptic (the path of the sun), then you’ll realize that they all rise in the east in more or less the same part of the sky. When I went out to take a picture of Cancer, I knew it would follow Gemini and I knew where I expected it to be… but I just could not find it!
When to Find Cancer
January & February are, in my opinion, the best months to see Cancer. Although it will stick around clear until June, after which it will descend into the sunset and make its way into the daytime sky. January and February are my preference to observe Cancer because during those months it is just rising in the eastern horizon at the beginning of the night. In later months, by the time it gets dark, Cancer will already be higher in the sky. I like to do most of my stargazing by looking into the low east for two reasons:
- It’s low, so I don’t have to strain my neck
- That’s where the new constellations appear as the earth rotates and orbits the sun.
I’ve found that’s a good way to gradually learn the sky. Since there are so many constellations, I pick two or three each month to learn, and by the next month there will be new ones in the same part of the sky! So there’s a little learning management tip, if you’re new to the constellations.
I should add though, that faint stars will be easier to see when they’re directly overhead because there’s less atmospheric interference, and usually less light pollution (from city lights, etc.).
Who is Cancer?
Cancer is Latin for Crab. The most common star pattern for this constellation looks like an upside down Y consisting of 5 stars. This is how it is defined by the International Astronomical Union, and although I’ve seen other patterns, I think it will make a good basis for my sketch. I can easily imagine a body and two pincers. I can also see a lobster in that shape—which is another common depiction of cancer, but I’ll stick with a crab for this one.
Where to Find Cancer
Remember how I couldn’t find Cancer when I went out to take my picture? Well, it turns out that cancer is one of the dimmest zodiacal constellations in the sky (second only to Pisces). To see it you’ll need a moonless sky, no clouds, minimal light pollution, and some time for your eyes to adjust to the dark.
Here’s the first picture I took. It was basically a blind shot, so… yeah I didn’t get even close to centering it in the frame. After some trial and error, I got a better picture! With a 2 second long exposure and some photoshopping we can clearly see the 5 brighter stars marked by the IAU’s pattern.
Look for Cancer in a dark part of the sky between Gemini and Leo.
Celestial Objects in Cancer
Here’s what to look for in Cancer:
Beta Cancri (Al Tarf): Beta Cancri is Cancer’s brightest star and also the furthest away of the brighter 5 stars you see in my picture. It is about 290 light-years away from the sun and is a Binary star system—that is, what looks like one star is actually two, locked in orbit with each other—which isn’t all that uncommon.
Delta Cancri: This star is 136 ly away. It’s babylonian name is the longest of all known star names, arkushanangarushashutu. Its latin name Asellus Australis means southern donkey (many stars have an Arabic name and a Latin name).
X Cancri: Is the reddest star in the sky according to StarWalk 2 and it’s near Delta Cancri.
Messier 44 (the Beehive Cluster) is a star cluster 515 light years away. Also known as Praesepe, which is Latin for Manger.The reason for this name was that ancient Greeks and Romans saw this object as a manger from which two donkeys, the adjacent stars Asellus Borealis and Asellus Australis, are eating.
M67 is another star cluster found near Cancer’s pincer, but this one is much harder to see. It is almost 3,000 ly away and they are very old, red stars, which don’t shine as bright.
That’s all for now! I hope you can find a quiet, dark place where you can enjoy the stars and find Cancer. If you’re lucky you might even see the Beehive cluster in the heart of the crab. Keep learning and remember to smile!
