As with anything new, you are bound to run into words and terms that are new or unknown to you.
Astronomy and the TAAS Fabulous 50 is no different. Here's a quick run-down of some common astronomical
terms you'll become familiar with at our sessions.
What is a constellation?
Constellations are imaginary things, figures in the sky that poets, farmers and
astronomers have made up over the past 6,000 years.
On a really dark night, you can see about 1000 to 1500 stars.
Trying to tell which is which is hard. We use constellations to help tell which stars are which.
The constellations help by breaking up the sky into more managable bits.
For example, if you spot three bright stars in a row in the winter evening, you
might realize, "Oh! That's part of Orion!" Suddenly, the rest of the constellation
falls into place and you can declare: "There's Betelgeuse in Orion's left
shoulder and Rigel is his foot."
Once you recognize Orion, you can remember that Orion's Hunting Dogs
are always nearby. Then you might recognize the two bright stars to the
upper and lower left of Orion as Procyon in the constellation Canis Minor and
Sirius in the constellation Canis Major.
Today's 88 constellations were formally defined in 1929 by the International Astronomical Union (IAU) so now every star in the sky is in exactly one constellation.
Here are some links with more information about the constellations:
General info - This is Wkipedia's extensive article on the
terminology, history and modern constellations.
IAU Site - Here the International Astronomical Union gives a brief discussion of constellations and provides links to maps of all 88 of them.
Constellation Photos - Naoyuki Kurita graciously has allowed us to use his photos for the Fabulous 50. Here's a link to all his constellation photos.
What is an asterism?
It's a pattern of stars that is not one of the 88 defined constellations. We use asterisms
to help navigate our way around the sky. The most famous of these is the Big Dipper
Many people think the Big Dipper is a constellation but it is just a part of the much larger
constellation, Ursa Major (Great Bear). You will learn to use famous asteriems and probably make up some of your own in the Fab 50 sessions.
What are the Messier Objects?
The Messier Objects are a set of over 100 astronomical objects first listed by French astronomer Charles Messier (shown at left) in 1771. Messier (pronounced MESS-ee-ay) was a comet hunter frustrated by objects that resembled but were not comets. He compiled a list of these objects, in collaboration with Pierre Mechain, to avoid wasting time on them. Today, the list comprises many of the best deep sky (that is, outside of the Solar Sytem) objects.
While very few Messier Objects are visible to the naked eye, all are visible in even a small telescope and many are observable in binoculars. In astronomy jargon, the objects are designated simply by a capital letter "M" followed by the number on the list. For example, the Andromeda Galaxy, one of the Fab 50 autumn targets, is M31.
The Messier list is vey popular in amateur astronomy and their are many great resources on the web about it. Here are links to a few:
Wikipedia - This includes a complete list with each item containing links to photos, definitions and individual articles on each Messier Object.
Locator Charts - This takes you to a pdf document with charts and additional information to help in locating each of th eobjects.
Astronomical League Site - The Astronomical League hosts many observing programs offering recognition for members who complete them. The Messier Program is very popular.