Capricornus constellation. Capricornus is a southern zodiacal constellation located between Sagittarius and Aquarius on the ecliptic. Alpha, Delta and Omega Capricorni are the three brightest stars in the constellation. Although Capricornus is the second faintest constellation, its mythology goes back more than 4,000 years. The Babylonians and Sumerians both referred to Capricornus as the Goat Fish. The constellation's brightest star Algedi, Alpha Capricorni, is a wide optical double star and gets its name from the Arabic word for the Goat.