This month, we continue down the Milky Way to our southern horizon.
To connect this map to the map found in June (Swan and Eagle), locate the last two stars in the Eagle’s tail. They are at the top of this month’s map and the bottom of last month’s. Just south of the Eagle, there is a small, dim parallelogram called Scutum, the Shield. You might not see it from a light-polluted area, but if you can see the Milky Way, you should find Scutum. The Milky Way in Scutum has been called the most beautiful that can easily be seen from Canada. Binoculars or a low-power telescope will reveal rich star fields. You might even be able to find M11, the “Wild Duck” cluster, and M17, the “Swan” nebula. Both are fairly prominent, and can get even prettier with more magnification.
Continuing southward, just above the horizon, you will find the teapot asterism that marks Sagittarius, the Archer. Now, I objected to hearing it called the Teapot at first, but it sure is easier to find! This small illustration shows the entire constellation – get to someplace dark and see if you can trace it all. I darkened the lines it shares with the teapot to get you started.
I have included four more Messier objects in Sagittarius. You should easily be able to find M8 and M20 in binoculars; M7 and M22 will be more challenging. The star fields of the Milky Way in Sagittarius and Scorpius are incredibly rich. This is hardly surprising, since the nucleus of the Milky Way, the hub of our great spiral-wheel of stars, lies buried in the dust and stars behind Sagittarius, some 30,000 light years away.
From Canada, Scorpius is best recognised by finding the orange star Antares, literally “Rival of Ares”. Ares is the ancient Greek name for the god of War that the Romans later named Mars. Scorpius and Sagittarius are on the ecliptic, that planet path, so ruddy Mars can pass fairly close to Antares. From Antares, look east and you will find a vertical arc of stars, representing the scorpion’s claws. The bright one in the middle is delta scorpii, or Dschubba. Keep an eye on it – starting in about 2000, it seems to be going through a mid-life crisis, and grew brighter over the next few years. Once the fifth brightest in the constellation, it is now second only to Antares. This extreme variability may be due to close passes of its companion (it’s a double or triple star) pulling material off its surface.
So there you have it – the Milky Way from zenith to horizon. Which area of the Milky Way do you like best? Cygnus with its dark lanes, Scutum with its rich star fields, or Sagittarius with its nebulae, clusters and star fields? On the other hand, why choose? Whether you take a scope, binoculars or just the eyeballs you were born with, go out and enjoy!