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What's Up...Dynamic duo arrives PDF Print E-mail

By Vernon Whetstone

Amateur Astronomer

 

At the beginning of July attention turns from the Summer Triangle, which has been rising higher in the east, to the southern skies with the arrival of the dynamic duo of Scorpius and Sagittarius.

Scorpius, the Scorpion is the classic “J” or fishhook shape located due south these evenings with bright Antares at its heart and its neighbor to the east is Sagittarius, the Centaur, or sometimes called the Archer.

Ancient celestial map makers depict Sagittarius holding out his bow with a deadly arrow pointed toward the scorpion. The rest of the body of the Centaur is, as with Pegasus, not depicted.

However, modern astronomers show Sagittarius as an asterism called the “tea pot.” The curved bow on the right has been changed into the right side of the teapot’s spout and the loop of stars on the left has become the handle.

There is also a sort of triangle of stars for a lid topped by a star named Kaus Borealis. Traditionally, Kaus Borealis marked the top of the archer’s bow, now it is the top of the teapot’s lid. The rest of the stars form the square body of the teapot.

The Milky Way runs between these two and is often called the steam coming out of the teapot’s spout. 

This area makes an excellent hunting ground for star clusters, nebulae, and other faint fuzzies. Two of the most interesting are the Triffid Nebula (M20) and the Lagoon Nebula (M7)

Both are located just above the tea pot’s spout and can be seen in the same binocular field of view. They are interesting in binoculars, but in a telescope they are fabulous. 

The center of the Milky Way Galaxy lies in the direction of Sagittarius. It is contained in the mass of stars in the steam just above the spout. 

It cannot be observed directly, there is too much dust and interstellar gas. It can, however, be examined with infra-red telescopes which see through the dust and records the heat of objects there.

And now for the promised tongue twister. It is the constellation Ophiuchus (pronounced OH-fee-YOU-kus), the Serpent Bearer. It can be located by following the Milky Way upwards to over and between Scorpius and Sagittarius. 

It is a fairly large almost rectangle group of stars. On either side are smaller, nondescript grouping of stars, Serpens Caput, the Serpent’s Head and Serpens Cauda, the Serpent’s Tail.

In mythology Ophiuchus is associated with Asclepius, thought to be the father of medicine and the healing arts. Along with the two parts of the serpent he is represented today in the Caduceus, the entwined serpents on a staff, the symbol of a doctor.

Technically Ophiuchus is located along the ecliptic, the path the Sun follows in a year thus making it a zodiacal constellation, the 13th sign of the zodiac. The Sun is in Ophiuchus from mid-November to mid-December, however, it is not considered part of the modern zodiac.

SKY WATCH: New Moon, July 11. Earth was at the farthest point from the Sun yesterday, July 6. If it was so far away from the Sun, why was it so hot you ask? Well, blame that pesky 23.5 degree tilt to Earth’s axis. The same tilt that gives us the seasons points the northern hemisphere so the Sun’s rays are falling more directly on Earth’s surface instead of the angular rays we get at other times of the year.

NEXT TIME: More astronomical blathering and another tongue twister.