What’s Up?: Sagittarius

Aug 3, 18 • 5enses, What's up?No Comments

By Adam England

August in Northern Arizona gives us some of the best views of the galaxy in which we reside — the Milky Way. So-called since ancient times, the Milky Way is named for its dense clusters of stars that create a “milky” swath across the sky. From our study of other galaxies, we’ve deduced that our own is a barred spiral galaxy with arms of star systems and nebulae stretching up to 180,000 light years from end to end. At the center of the Milky Way — as well as at the center of almost all other known massive galaxies — lies a super-massive black hole named Sagittarius A* (pronounced “Sagittarius A-Star”). The many stars in relatively close proximity to each other and in perpetual orbit around Sagittarius A* form the basis of one of the longest recognized constellations, Sagittarius.

Sagittarius is the archer in Babylonian and Greek mythology, usually depicted as a half-man/half-horse, i.e. a centaur, drawing his bow. His arrow points to the heart of Scorpius — the bright red star Antares — should the scorpion ever attempt to attack Hercules after his triumph over the hunter Orion.

Sagittarius astral photography by Jeff Stillman, Prescott Astronomy Club president, taken taken through a 14” SCT with 12MPX Atik 4120 One Shot Color Camera. The image is a stack of 20 frames, each of 10 minute exposures.

The most recognizable stars of the constellation form what is known as “The Teapot,” with a handle and spout. The Milky Way rises to the Northwest as a puff of steam rising from the kettle. The handle of the teapot forms the Archer’s shoulder, with dimmer stars mapping the outline of the horse-like body.

The Lagoon Nebulae (Messier 8 or M8) is one of the many deep-sky objects we can see with a backyard telescope. Just 5,000 light years distant from Earth, and measuring 140 light years by 60 light years, it comes in at magnitude 3.0. Although it appears grey to the visual observer, a long exposure photograph of the nebulae reveals its beautiful pink coloring, as is common of other emission nebulae.

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Visit Prescott Astronomy Club at PrescottAstronomyClub.Org and find out about upcoming star parties, Star Talks, and more. Contact them at Contact@PrescottAstronomyClub.Org.

Adam England is the director-at large and in charge of public relations for the Prescott Astronomy Club.

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