The Transylvania Times -

The Stars

The Summertime Milky Way is now high overhead at sunset! While this beautiful veil in the sky may have been obvious to the casual observer in years gone by, nowadays bright urban skies require some planning and effort to enjoy it. However, all one really needs is a dark night with a clear view of the sky; some of the overlooks on the Blue Ridge Parkway and the campus at PARI provide gorgeous views not only of the mountains during the day, but also the stars at night.

Start by looking a little to the west of due south and you will find our old friends Scorpius and Sagittarius. The center of the Milky Way is in the direction of Sagittarius and, for this reason, this area of the sky is rich in the nebulae and star clusters so popular with astronomers. If you have a pair of binoculars handy, lean back in your lawn chair and enjoy this rich area of the sky.

Now follow the band of the Milky Way upward until you are looking straight overhead. Notice a pattern of six stars that looks like a large cross in the sky. While some people call this pattern The Northern Cross, it is officially the constellation of Cygnus, the swan. In Greek mythology, Cygnus was the friend of Phaeton, the son of Helios, god of the sun. Helios had the job of driving the sun chariot, pulled by four horses, across the sky each day. One day, Phaeton “borrowed” his father’s chariot and tried to drive it himself. But he could not control the spirited horses and, with a little help from a thunderbolt thrown by Jupiter, soon fell out of the chariot landing in the river Eridanus. Cygnus saw this and time and again dove into the river until he had recovered the mortal remains of his friend. Jupiter rewarded this act of friendship and loyalty by turning Cygnus into a beautiful swan and placing him in the sky. We find Cygnus with his tail and long neck stretching along the Milky Way, which represents the river Eridanus.

It is in a small select section of this area of the sky that the Kepler spacecraft carried on its initial search for extrasolar (beyond our solar system) planets. On Oct. 30, 2018 NASA declared the end of Kepler’s extended K2 mission when it ran out of the fuel necessary to keep the spacecraft properly oriented in orbit. As of the end of its nine years of observations, Kepler had discovered 2,734 confirmed extrasolar planets. (Visit NASA’s site http://www.nasa.gov/kepler/discoveries for more details.)

The Planets

The two gas giant planets continue to grace in our early evening sky. Look for the giant Jupiter low in the southwest as twilight deepens. Since it is the brightest object, except for the moon, up tonight, we should have no problem spotting it. Jupiter will be with us until it sets about midnight. At that point, it leaves the ringed planet Saturn as the only visible planet in the sky.

At sunset, Saturn was pretty much due south. These nights it appears low in our southern sky as it hangs around the handle of the teapot asterism in the constellation of Sagittarius, the archer. Saturn is lagging Jupiter by about two hours and, so, it will set shortly after 2 a.m. EDT leaving the sky empty of visible planets for the rest of the night.

Whenever a planet is lined up behind the sun as viewed from the earth, astronomers say it is in superior conjunction. Conjunction means two objects are lined up and superior refers to the opposite side of the sun. (Both Mercury and Venus could be in conjunction with the sun on Earth’s side of out central star; this would be inferior conjunction. Mars never comes to inferior conjunction. Why?) In the past month we have experienced all three of the terrestrial planets passing through inferior conjunction: Venus on Aug. 14, Mars on Labor Day, Mercury less than two days later. What that means for us this week is that all three are still roughly behind the sun. Thus, these three planets are lost in the glare of the sun for at least the first half of the month. We will have better luck in this respect late in the month and certainly next month.

Celestial Calendar

Sept. 14, 12:33 a.m. EDT - Full Moon (Harvest Moon).

Sept. 16 - The sun, in its apparent path around the sky, moves from Leo, the lion, into Virgo, the maiden. Virgo personifies Ceres, the ancient goddess of the harvest, and we derive our English word “cereal” from her ancient name.

Sept. 21, 10:41 p.m. - Last quarter moon.

Sept. 23, 3:50 a.m. EDT- Autumnal equinox. First moment of autumn.

(The Learning Center at PARI is a public not-for-profit 501 (c) (3) organization established in 1998. Located in the Pisgah National Forest, the Learning Center provides STEM educational programs at all levels, from K-12 through post-graduate research. For more information about the Learning Center at PARI and its programs, visit http://www.pari.edu.)