By Mike P. Usher
Tonight the two brightest, or at least the easiest to find, constellations of the zodiac are riding high in the sky; Sagittarius the Archer or Centaur (actually it’s both) and Scorpius the Scorpion are easy to locate. Sagittarius has the famous teapot asterism that really jumps out of the jumble of stars that fill this region of the sky; and Scorpius is one of the very few constellations that actually look like the thing they are supposed to represent.
The teapot asterism consists of eight stars all roughly equally bright; this time of year the teapot appears level as if sitting on a stove, but in the fall it tips over and appears to be pouring out it’s load of tea. Fairly close to the tip of the teapot’s spout is the direction to the center of our galaxy and the giant black hole at it’s heart. We see nothing of this as this whole area is choked with gas and dust obscuring our view – but astronomers can use infrared cameras and radio telescopes to get a look.
Here in Florida Scorpius rides fairly high in the sky, from the northern U.S. or Canada the tail grazes the trees on the horizon; on Marco we can even see the rather faint constellations underneath the stinger. Antares is the bright red eye of the scorpion, one of only two red supergiant stars visible with the naked eye. (The other one is Betelgeuse.) Antares has a faint green companion discovered by accident when the Moon briefly covered the bright red star, allowing the faint companion to shine out on it’s own. Such an event is called an occultation and are not uncommon although bright stars like Antares being covered are modestly rare.
As Sagittarius and Scorpius are buried in the Milky Way there are a number of binocular objects scattered thickly about and between the two. In particular make the effort to locate M22 a bright globular cluster just to the left of the teapot’s top star and M4, another globular cluster sitting right next to Antares. For open clusters you can check out M25 and the Butterfly cluster, and for nebulosity M21, the Trifed Nebula and the nearby Lagoon Nebula.
See you next time!
Mr. Usher is President of the Everglades Astronomical Society which meets the second Tuesday each month during the summer at 7:00PM in the Books-A-Million, at the Mercato, Naples.