Tonight is a good time to look at Capricornius the Sea Goat.
Astronomical twilight ends at 7:36 p.m and the moon won’t rise until 11:32, giving us four hours of dark evening sky.
Look directly south around 9 p.m. Capricornius (sometimes spelled Carpricornus) will be 40 degrees above the horizon. Capricornius, which actually looks like a flattened bowl with a wide mouth facing north and a pointed bottom facing south, is faint and uninspiring as far as constellations go — but once found, it is easily recognized.
Capricornius’ big fame is its being a member of the zodiac. Because the Earth revolves around the sun in a year’s time, the sun appears to travel through the sky on a path known as the ecliptic. Most of the planets are close to the ecliptic, and their paths around the sky are confined to the narrow zone known as the zodiac, which stretches about 9 degrees on either side of the ecliptic.
The 12 main constellations through which the ecliptic and the sun and planets pass are the Zodiacal Constellations: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Sagittarius, Capricornius, Aquarius, and Pisces. The “signs of the zodiac” were established several thousand years ago when astrology and astronomy were closely related. However, modern astronomers no longer follow the tenets of astrology, and the two disciplines have gone their separate ways.
The International Astronomical Union standardized formal constellation names and boundaries in 1933 to prevent confusion.
In this process, the zodiac gained a 13th constellation Ophiuchus, because its modern boundary overlaps the zodiac.