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Ophiuchus, 13th constellation of Zodiac

Fantastic meteor shower prospects this year! See EarthSky’s meteor guide for 2016

Tonight, look for the faint constellation Ophiuchus the Serpent Bearer. From the Northern Hemisphere, look southward at mid-to-late evening in July. From the Southern Hemisphere, look around this same time, but overhead. From all parts of Earth in the month of July, Ophiuchus descends westward as Earth spins under the sky, and evening deepens into late night. Ophiuchus is sometimes called the 13th or forgotten constellation of the Zodiac.

The sun passes in front of Ophiuchus from about November 29 to December 17. And yet no one ever says they’re born when the sun is in Ophiuchus. That’s because Ophiuchus is a constellation – not a sign – of the Zodiac.

Ophiuchus in Urania’s Mirror, a boxed set of 32 constellation cards first published in 1824. Image via www.ianridpath.com.

Ophiuchus in Urania’s Mirror, a boxed set of 32 constellation cards first published in 1824. Image via www.ianridpath.com.

What’s the difference? The 12 signs of the Zodiac represent equal 30o divisions of sky, while the 13 constellations of the Zodiac are of various sizes.

That’s why, for example, the sun resides in front of each zodiacal sign for a precise interval of about a month. Meanwhile, the sun is in front of the constellations for varying amounts of time, for example, in front of Virgo for about one-and-a-half months and in front of Scorpius for about a week.

In 2016, a planet can help you find Ophiuchus in the night sky. An imagainary line drawn from the bright red star Antares in the constellation Scorpius the Scorpion – through the planet Saturn – points right to Ophiuchus on these July 2016 evenings. Incidentally, in 2016, you’ll also see the red planet Mars and golden planet Saturn forming a bright triangle of lights with Antares.

An imagainary line drawn from the star Antares through the planet Saturn points right at the constellation Ophiuchus the Serpent Bearer on these July 2016 evenings.

Use the star Antares and planet Saturn points to find Ophiuchus the Serpent Bearer in 2016.

Even after Mars and Saturn move to other parts of the sky, you can look for Ophiuchus near Antares on the dome of night. Ophiuchus’ brightest star – called Rasalhague – highlights the head of Ophiuchus. It’s nowhere as bright as the star Antares (or, in 2016, the planets Saturn or Mars).

Ophiuchus will remain visible near Antares, Mars and Saturn through August and September, 2016.

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Ophiuchus the Serpent Bearer, via Wikimedia Commons.

Ophiuchus the Serpent Bearer, via Wikimedia Commons.

On sky maps, Ophiuchus the Serpent Bearer is depicted as holding Serpens the Serpent, which is considered a separate constellation. According to ancient Greek star lore, Ophiuchus is Asclepius, the physician who concocted a healing potion from the Serpent’s venom, mixing it with the Gorgon’s blood and an unknown herb. This potion gave humans access to immortality, until the god of the underworld appealed to Zeus to reconsider the ramifications of the death of death.

Even today, the Staff of Asclepius – the symbol of the World Heath Organization – pays tribute to the constellation Ophiuchus the Serpent Bearer.

Bottom line: Will you see faint Ophichus, the overlooked zodiacal constellation, tonight?

Read more: Born between November 29 and December 18? Here’s your constellation

Dates of sun’s entry into each constellation of the Zodiac

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Bruce McClure

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