Remember What The Dipper Said

The Big Dipper is a veritable cornucopia of astronomical mind food. I think its shape even resembles the famed Horn of Plenty, which is a symbol of the Thanksgiving holiday, a lot more than what it's supposed to be – the body and tail of a bear. Ever notice that bears have very short tails, not long ones like the handle of the dipper? Even very primitive cultures had myths that explain how it got to be so short. If the Greeks were so smart, why didn't they know that? But I digress.

Oh! That reminds me. While we're digressing, we might as well get one thing out of the way early in the game: the Big Dipper is not, strictly speaking, a constellation. It's a group of stars that is part of a constellation called "Ursa Major," the Great Bear.

The Official 88 Constellations have been determined by an organization of astronomers. The question of who died and made them god is a question that involves class and political issues we'll steer clear of here.

But just for the record, certain famous groups of stars – such as the Big Dipper, the Seven Sisters, and the Summer Triangle – that have taken on lives of their own in the popular imagination, but which do not bear the imprimateur of the official board of self-appointeds, are known as asterisms.

On the one hand this is a perfectly descriptive term: it comes from the Greek root meaning, "star," and is related to other familiar words, such as "asterisk" and "disaster" (and, yes, "astronomy"). On the other hand, it really is a clumsy word and it serves a distinction that's important only to professional astronomers and certain geeks. For our purposes, the Big Dipper is a constellation, and we're going to be loosie-goosie about terminology when it doesn't matter, so that's what we're going to call it.

The preceding rant was hopefully not only informative, but permissive: please feel free to use your own imagination when fleshing out the constellations, but keep in mind we all need to speak a common language. So, sometimes we'll play their game, but we don't have to think it's the only game in town.

So, back to the Cornucopia. Or, ahem, the Big Dipper. Here's how it's typically depicted:

It looks like a dipper or saucepan with an ergonomic handle. (The British think it looks like a plough.) The "pointer stars" are the two on the far right. They have names – Dubhe and Merak (Merak is on bottom; Dubhe is on top) – or you can just call them, The Pointer Sisters. Here's a picture of them pointing:

The star in the green circle is Polaris, the North Star. Polaris is a star in another constellation: The Little Dipper, which resembles its larger sister, except that the handle bends the other way. The Little Dipper is an asterism in the constellation, Ursa Minor, The Little Bear.

This is the secret of naked astronomy, which amounts to using the pointer stars in any constellation to go "starhopping" to the others. Eventually, you get so good at it that you can start with any constellation you recognize. But for now, use the Big Dipper and Orion as starting points. Soon, you'll have worn pathways all across the sky.

Now, hang on to your bridgework. We're about to do a loopty-loop!

Comparing the last two illustrations of the Big Dipper on this page, you'll notice they each tilt the constellation differently. That's not because the artists held their computers at different angles. The reason for the tilt is the second secret the Big Dipper has for us.