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Constellations of the Southern Autumn Help

By — McGraw-Hill Professional
Updated on Sep 16, 2011

Constellations of the Southern Autumn—Libra

Imagine that it is still the same night and still the same time (10:00 ), and you turn your attention toward the east, north, and west, that part of the sky not confined to the vicinity of the celestial pole. Constellations in this part of the sky rise and set; they are not always above the horizon. As is the case in the northern hemisphere, the farther from the pole a constellation is located, the more time it spends each day below the horizon. A star at the equator spends exactly half the sidereal day, or about 11 hours and 58 minutes, above the horizon and half the time out of sight “beneath Earth.” Ultimately, for observers at 35 degrees south latitude, constellations with declinations of more than +55 degrees (within 35 degrees of the north celestial pole) never make it above the northern horizon.

Libra

Libra is a group of faint stars representing the scales of justice. It is high in the northeastern sky. It has the general shape of a trapezoid or diamond at this time of the year (Fig. 3-12).

The Sky “Down Under” Constellations Of The Southern Autumn Libra

Figure 3-12. Libra, the scales of justice, looks like a diamond.

Virgo

Virgo , the virgin, is fairly high in the north-northeast sky. As viewed from this angle, it is shaped rather like a scorpion (Fig. 3-13). Virgo contains the bright star Spica .

The Sky “Down Under” Constellations Of The Southern Autumn Virgo

Figure 3-13. Virgo, the virgin, looks something like a scorpion.

Leo

Leo , the lion, is high in the northwest sky. It bears no resemblance to a resting lion or Sphinx, as it does when looked at from north of the equator. Instead, its shape more nearly resembles that of a mangled coat hanger (Fig. 3-14) or a laundry iron held upside down. The bright star Regulus dominates.

The Sky “Down Under” Constellations Of The Southern Autumn Cancer And Canis Minor

Figure 3-14. Leo, the lion, lacks his regal nature south of the equator.

Cancer And Canis Minor

Cancer , the crab, is low in the northwest sky (Fig. 3-15). Next to Cancer is Canis Minor , the little dog, which contains the prominent star Procyon . In ancient Greek mythology, souls were said to enter the world by passing down from the heavens through Cancer.

The Sky “Down Under” Constellations Of The Southern Autumn Cancer And Canis Minor

Figure 3-15. Cancer, the crab, and Canis Minor, the little dog.

Corona Borealis

Low in the northeastern sky, near the horizon, is a group of several stars that form an inverted-U or Greek letter omega shape. These stars form the constellation Corona Borealis , the northern crown (Fig. 3-16). This constellation is dominated by the moderately bright star Alphecca , also known as Gemma .

The Sky “Down Under” Constellations Of The Southern Autumn Corona Borealis

Figure 3-16. Corona Borealis, the northern crown.

Bootes And Canes Venatici

Just to the left of the northern crown you will see a brilliant, twinkling star at an elevation of about 20 degrees in the northeast or north-northeast sky. This is Arcturus . If you use your imagination, you might see that this star forms the point where a fish joins its tail (Fig. 3-17). The fish seems to be swimming straight downward. This is Bootes , the herdsman. Just to the left of Bootes, near the northern horizon, is a group of three rather dim stars. These are Bootes’ canine companions, Canes Venatici .

The Sky “Down Under” Constellations Of The Southern Autumn Corvus, Crater, And Hydra

Figure 3-17. Bootes, the herdsman, and Canes Venatici, his dogs.

Corvus, Crater, And Hydra

A large portion of the autumn evening sky is occupied by three constellations consisting of relatively dim stars. These are Corvus , the crow, Crater , the cup, and Hydra , the sea serpent or water snake (Fig. 3-18). Hydra stretches from low in the northwest, nearly through the zenith, to high in the eastern sky. Corvus and Crater are both high in the north, just below Hydra.

The Sky “Down Under” Constellations Of The Southern Autumn Corvus, Crater, And Hydra

Figure 3-18. Corvus, the crow; Crater, the cup; and Hydra, the sea serpent.

Practice problems of this concept can be found at: The Southern Sky Practice Problems

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