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Sagittarius - the Archer


Mythology - Sagittarius is sometimes, and incorrectly, identified as the centaur Chiron. Sagittarius actually represents the son of Pan named Crotus. Living on Mount Helicon with the Muses, he became their friend and protector. He invented applause as a sign of appreciation for their talents. A skilled hunter and good friend to the Muses, they asked that Zeus give him a constellation fitting his kind nature. With the goat-god Pan as his father, Crotus should be considered a satyr rather than a centaur. His depiction as a centaur probably came from his superb riding skills.
Stars - W sagittarii is a cepheid variable with a period of 7.6 days. It oscillates in brightness from mag. 4.3 to 5.1. RY sagittarii is another “sooty” star, similar to R corona borealis. It can suddenly dim down from mag 5.8 to 14 as dark clouds of carbon are blown off its surface.
Deepsky - There are four superb emission nebulæ visible in the constellation of Sagittarius. All of
these objects are regions of active star formation that look fascinating through a telescope. M20 - the Trifid Nebula is a naked eye object, but looks very good through binoculars. You may be able to resolve the three dark dust lanes that give it its name. M8 - the Lagoon Nebula is much larger object, but it is fainter. A naked eye fuzz becomes a glowing halo in binoculars. M17 (the Swan Nebula) and M16 (the Eagle Nebula) are fainter than the other two, although higher up in the sky and requires binoculars to see them. Sagittarius plays host to the following bright open clusters: M18, M21, M54 and M55. Many of these are naked eye objects. There is a good globular cluster too, M22.
Visibility - Sagittarius is the most difficult zodiac sign to see from the Uk since it has the largest southern declination. The best time to see it (and any planets moving through it) is in August or September