The Sea Goat in the Skies: The ancient constellation Capricornus bears an interesting history.
Why do I find it so compelling? First of all, no other constellation represents something so peculiar--a creature half-goat and half-fish. Yet its strange goat-fish form is also the key to directly identifying it as one of the most ancient of all constellations. Other notable attributes of Capricornus include its compactness, its rich connections with language, its remarkable double stars, and its position with regard to the zodiac, the Summer Triangle, and certain deep-sky objects.
Capricornus, the compact stand-out. At the time of our October all-sky map, the pattern of Capricornus is at its exact highest in the south. Capricornus is fairly dim, though certainly no more so than the other two constellations that form the autumnal zodiac, Aquarius and Pisces. But according to the modern boundaries of the constellations, the area of the heavens that belongs to Capricornus is actually smaller than that of any other zodiac constellation, even a little smaller than that of Aries. Aquarius and Pisces are both more than twice as big in area as Capricornus (so is Capricornus's western neighbor, Sagittarius--and Virgo is more than three times larger). But the fact that the pattern of Capricornus is rather compact makes it easier to find and study than the more sprawling and complicated forms of Aquarius and Pisces.
What should also be quite noticeable to those who follow the planets is how large the gap--consisting of mostly faint and disorganized starry heavens--actually is between the Teapot of Sagittarius and the interesting western end of Capricornus. Of course, in recent years the Teaspoon asterism in Sagittarius has (rightfully) gained greater fame. But the naked-eye dullness of eastern Sagittarius still may be the largest such gap anywhere along the zodiac--and western Capricornus is at the end of that gap.
The goat or boat Astronomy writer Guy Ottewell has said that the pattern of Capricornus looks more like a boat than a goat--though I would say a oddly formed little paper boat or an origami bird. However, we now know that Capricornus was indeed imagined to be a boat--the boat of the god Enki --in Mesopotamia about 5,000 years ago (S&T: Mar. 2015, p. 36). Interestingly, only a few hundred years later the pattern became associated with one of Enki's various forms--front-half goat and back-half fish. And up to our present day, Capricornus is still pictured that way. It is supposed to be a "Sea Goat" or "Goat-Fish."
Capricornus in name and Ian-The name Capricornus is Latin for "horned goat." The second half of the name is the "horn" part: A cornucopia is a horn of plenty ("copia" as in copious) and a mythical one-horned creature is a unicorn. But the first part of the name Capricornus means "goat"--baby goats (kids) hopping around playfully are capering, and we call their behavior capricious. One of several possibilites is that the age-old Italian resort, the Isle of Capri, was named for being the "isle of goats." At the very time of our October all-sky map, with Capricornus at its highest, the brilliant star just rising in the northeast is Capella, which means "she-goat" (the mother goat held by Auriga, the Charioteer).
Capricornus to be continued. The head of the Sea Goat is marked by Alpha ([alpha]) and Beta ([beta]) Capricorni, just a few degrees apart--with Alpha a wide naked-eye double star and Beta a wide binocular double star. Next month we'll examine them, plus several other choice deep-sky objects in and near Capricornus. We'll also consider other fascinating aspects of Capricornus's positioning and objects to which its odd shape has been compared.
* Contributing Editor FRED SCHAAF welcomes your letters and comments at email@example.com.
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|Title Annotation:||Under the Stars|
|Publication:||Sky & Telescope|
|Date:||Oct 1, 2018|
|Previous Article:||OCTOBER 2018 OBSERVING: Planetary Almanac.|
|Next Article:||Enter the Ice Giants: The brighter planets begin to give way as Uranus and Neptune jostle for our attention this month.|