Constellations of Summer Help

Constellations of Summer—Capricornus

Capricornus

Near the horizon in the east-southeast sky is a group of stars whose outline looks like the main sail on a sailboat. This constellation is Capricornus (often called Capricorn ), the goat (Fig. 2-17). This goat has the tail of a fish, according to the myths, and dwells at sea. On its way to heaven after the death of the body, the human soul was believed to pass through this constellation; it is 180 degrees opposite in the celestial sphere from Cancer, through which souls were believed to enter this world.

Figure 2-17. Capricornus, the goat, has the tail of a fish.

Sagittarius

In the east-southeast sky, to the right and slightly above Capricornus, you will see a constellation whose outline resembles a teapot (Fig. 2-18). This is Sagittarius , the centaur. What, you might ask, is a centaur? You ought to know if you have read mythology or seen a lot of movies or television; it is a creature with the lower body of a horse and the chest, head, and arms of a human being. The centaur carries a bow and arrow with which to stun evil or obnoxious creatures. Sagittarius lies in the direction of the densest part of the Milky Way, the spiral galaxy in which our Solar System resides.

Figure 2-18. Sagittarius, the centaur, is shaped like a teapot as viewed from northern-hemispheric temperate latitudes.

Scorpius

A huge and hapless scorpion, forever on the verge of feeling the bite of Sagittarius’s arrow, sits in the southern sky, extending from near the horizon to an elevation of about 30 degrees (Fig. 2-19). This is Scorpius (also called Scorpio ). This constellation is one of the few that bears some resemblance to the animal or object it represents. The eye of the scorpion is the red giant star Antares , which varies in brightness.

Figure 2-19. Scorpius, the scorpion, contains the red star Antares.

The Summer Triangle

If you stand facing east and look up near the zenith, you will see the bright star Vega , flanked by a small parallelogram of dimmer stars. The quadrilateral forms the constellation Lyra , representing the lyre played by the mythical musician Orpheus. Below and to the left of Vega is another bright star, Deneb , that is at the tip of the tail of Cygnus , the swan. If you are at a dark location away from city lights on a moonless summer evening, you might imagine this bird soaring along the Milky Way that stretches from the north-northeastern horizon all the way to the southern horizon. Off to the right of these is a third bright star, Altair . This is part of the constellation Aquila , the eagle that pecks eternally at the liver of Prometheus as part of his punishment for stealing fire from the gods. Vega, Deneb, and Altair stand high in the east on summer evenings and comprise the well-known summer triangle (Fig. 2-20).

Figure 2-20. The Summer Triangle is formed by the stars Vega, Deneb, and Altair, in the constellations Lyra, Cygnus, and Aquila (the lyre, the swan, and the eagle).

Ophiuchus And Serpens

In the southern sky, centered at the celestial equator, is the constellation Ophiuchus , the snake bearer. This poor soul holds a snake, the constellation Serpens , that stretches well to either side. You might imagine that Ophiuchus has a meaningless job, but nothing could be further from the truth. Ophiuchus must keep a tight hold on Serpens (Fig. 2-21), for if that snake gets away, it will easily be able to reach and bite Bootes, the herdsman. If that were to happen, Bootes and his dogs, Canes Venatici, would stop driving Ursa Major around Polaris, and Earth would stop spinning!

Figure 2-21. Ophiuchus, the serpent bearer, holds Serpens, the snake. The snake’s head is but a small distance from the back of unsuspecting Bootes.

Coma Berenices

About halfway between the horizon and the zenith in the west-northwest sky, you will see a fuzzy blob. With binoculars, this resolves into a cluster of stars known as Coma Berenices (the hair of Berenice). Some people mistake this group of stars for the Pleiades. However, the Pleiades are best observed in the winter.

Practice problems of this concept can be found at: Stars and Constellations Practice Problems