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Introduction to Constellations

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Since the beginning, mankind has looked at the distant stars trying to make sense of their patterns. It is human nature to “connect the dots” in a meaningful fashion. Throughout history, all cultures and civilizations have associated constellations with myth and legend.

The word constellation is the name of a starry group forming a recognized pattern. Twelve are located along the ecliptic plane—the “signs” of the zodiac: Aquarius, Aries, Cancer, Capricorn, Gemini, Leo, Libra, Pisces, Sagittarius, Scorpius, Taurus and Virgo. The celestial sphere contains 88 constellations. Let’s use a simple exercise to explain movement.

On paper, draw a simple pentagon pattern of 5 stars with the top star largest and each a different size. Astronomers identify constellation stars by assigning them Greek letters—starting with alpha for the brightest. Assign each star in your constellation a letter by starting with the biggest and the brightest. This is how a star chart works.

This represents our “learning constellation” and we’ll begin with the north celestial pole. By aiming the large star at the imaginary pole, rotate your constellation in a counter-clockwise circle. As it circles the pole, it first appears to lie on its side, be upside down, lie on its other side, then be right side up! No matter what way it turns as it takes its journey—the top star is aimed at the North Pole.

Let’s pretend our learning constellation passes overhead and you’re facing south. Hold it in your left hand with the top star pointed behind you (north). Let’s watch it rise in the east! Pass it straight overhead, take it with your right hand and make it set west. Now our learning constellation looked almost the same on its journey! The top star always pointed north and the side that rose first was the first to set.

Now point our learning constellation to the south celestial pole. But remember—we can’t see it because of the horizon. Our top star would always point to the south, but we’d see it make a shallow arc. It would rise on its side in the southeast, its top star pointed south, turn upside down as it reached its highest point above the horizon, and set on its opposite side to the southwest.

Next Page: What constellations can be seen in the Spring?

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