A group of stars that forms a picture is commonly called a constellation. Astronomers, however, call these star pictures asterisms, and have a slightly different definition of a constellation. Scientists divide the sky into eighty-eight official constellations, so that every point in the sky is contained within only one. As you peruse today's crop of sites, keep both these definitions in mind, because some sites use the astronomer's definition, and others do not.
This interactive night sky map is so easy to use, it barely needs any explanation. To begin, click Start and enter your location. By default, the constellation outlines and names will display for today's date. Some details display by hovering your mouse over the labels, others require a mouse click. Additional options, such as displaying Latin constellation names, or dwarf planets, are available on the More button.
Richard Dibon-Smith, an astronomy fan since childhood, built The Constellations based on his popular self-published constellation guides. It is an outstanding resource for students writing reports, as well as budding stargazers. Each of the eighty-eight constellations is listed along with their Greek myth (if they have one), unique stats and unusual features such as any deep sky objects that may be part of the constellation. Each constellation also has a star chart. To view it from the constellation detail page, click one more time on the name of the constellation.
Google Sky is an interactive, searchable map of the night time sky. Click on the Constellations button (look for it along the bottom of your browser window) to superimpose any of the zodiac constellations on the sky map. As you mouse along the map, notice the numbers changing in the lower left corner? This is your current location in the sky, measured in right ascension and declination, a celestial coordinate system used by astronomers.
This section of the Deepsky Atlas from the Hawaiian Astronomical Society lists the eighty-eight constellations alphabetically. The detail pages include related myths, a variety of maps, and star photos. I was fascinated by the interactive maps. Click on the thumbnail to display a full-size clickable, interactive star map. "The first map is a wide area view of the constellation, suitable for naked eye browsing. The next views are binocular width, showing stars to magnitude 10, and labeling deepsky objects to magnitude 12."