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Constellations and Asterisms
Constellations have been an important part of human society and folklore since we humans lived in caves, and, probably, even before then. The fascinating figures that we see in the night sky are so large and so beautiful that we have felt a very strong urge to attach importance to them. People have done this throughout the ages by creating very interesting stories and legends in an attempt to explain where these large "pictures" in the sky came from. These stories, also known as mythology, behind the constellations can be as interesting as studying the constellations themselves.
There are currently eighty-eight figures in the sky that have been generally recognized as being "official" constellations by whoever it is that designates such things. We aren't going to list all of them, since that has been done in several other places on the internet. What we are going to do is pick a few of them that are easy to find no matter whether you live in the city or the country. We will tell you where to look for them and when during the year you can expect to see them. We will also give you a simple chart that you can use that should help you identify the constellation in the sky.
In addition to a few of the constellations, we will also give you guides to a few "asterisms", which aren't officially constellations, but are easily recognizable patterns of stars that are either parts of a larger official constellation, such as the Big Dipper, or just good landmarks, like the Summer Triangle.
Enjoy your trip through these fascinating residents of our night sky!
One of the most impressive sights in the winter sky, Andromeda appears high overhead during November and December. In addition to being easy to find, this constellation also has the large Andromeda galaxy as a close neighbor.
The Big Dipper
Since the Big Dipper is part of the constellation Ursa Major (The Great Bear), it is technically an asterism and not a true constellation. However, it is one of the most familiar figures in the night sky and can act as a guide to other interesting sights. It also played an important part in United States history.
Canis Major - The Great Dog
Every hunter needs hunting dogs as companions. Canis Major and Canis Minor are the hunting dogs for Orion, the Great Hunter of the sky. In addition, Canis Major is home to Sirius, the brightest star in the night sky.
Cygnus - The Swan
This great bird soars high in the night sky during the early morning in late summer and in the evening during the fall. One of Cygnus' stars is also one of the corners of the Summer Triangle asterism.
Gemini - The Twins
The Twins are companions of Orion in our night sky. Gemini is visible in the early morning skies during fall and eary winter and in the evenings during winter.
Leo - The Lion
Leo is another member of the group of constellations around Orion. Its distinctive shape makes it easy to find whenever Orion is visible.
Orion - The Great Hunter
Orion is the largest constellation in the sky. This giant figure dominates the sky in the early mornings in late summer and fall, and in the evenings during the first part of winter. It also has several really interesting things you can see with just a pair of binoculars.
Scorpius - The Scorpion
Scorpius is one sign that summer is in full swing in the northern hemisphere. This beautiful constellation is in full view in the southern sky only during the months of July, August and September, but its beauty makes it worth the wait.
Taurus - The Bull
Another companion of Orion, Taurus is located directly above the Hunter in the sky. In addition to the giant red star Aldebaran, Taurus is the home of the Crab Nebula and the Pleiades cluster.
Finding the Constellations in the Sky
Although we have provided maps and charts for all of our example constellations, and given general times when you can see them, it is still very difficult to accurately show our three-dimensional sky on a flat screen like your computer monitor.
All of the constellations and asterisms we show you are actually quite large in the sky. We will use Orion as a general example. If you hold your hand out at arm's length and spread your fingers, Orion will be at least as large as your hand is.
Keep this in mind when you are just getting started finding the constellations. Once you have found the really big ones, like Orion and the Big Dipper, you will get use to looking for, and recognizing, the patterns of the constellations. It's actually pretty easy once you get started.
What Are Those Odd "M" Numbers
In several of our example constellations, like Orion, we make reference to objects like the Orion Nebula and have an "M" followed by a number. In the case of the Orion Nebula, this number is M42. The "M" stands for Charles Messier, who was a French astronomer that lived on the eighteenth century. His main passion was searching for comets and he made a list of objects in the sky that weren't comets and put them into a catalog.
The objects in this catalog were identified by his initial M and a number indicating the order in which he cataloged them. This catalog, called, appropriately enough, the Messier Catalog, and is still in use today.
- Chris Dolan's Constellations Site
- Chris Dolan's constellations site has lots of good reference information about the constellations and their stars.
- Hawaiian Astronomical Society Site
- The Hawaiian Astronomical Society's site has an excellent constellation reference as well as sections about the sky in general.
- Richard Dibon-Smith's Constellations Site
- Richard Dibon-Smith's constellations site is an excellent place to learn the mythology and legends behind the constellations.
- Nightwatch by Terence Dickinson
- "Nightwatch" is an excellent book with very good, easy to read sky charts and maps. In addition to the excellent charts and maps of the constellations, it has lots of very good information about observing in general. Highly recommended.
- Information about Charles Messier
- This page has a brief biography of Charles Messier and a link to the complete catalog of Messier objects.