By David Ward
The foliage in the high country is starting to change color and flocks of geese are on their way south. These are signs that the seasons are changing. Ancient people believed that everything important was written in the stars, and we can see the change in the seasons up there also.
The stars are in a different place in the sky than they were last summer. The earth is barreling along in its orbit around the sun at 19 miles per second — almost 67,000 miles per hour. Due to the elliptical orbit of the earth, we travel a little faster in the winter and a little slower in the summer. The space ship Apollo 11 took four days, six hours and 45 minutes to get to the moon. The earth covers that distance in a little under four hours. Of course, we never get there because the moon being gravitationally attached to the earth, tags along with us in our journey around the sun.
Our travels through space give us a changing perspective on the universe. Look up into the night sky, and if you are acquainted with the stars, you will notice that they are shifting to the west. New constellations are appearing in the east.
The Summer Triangle, that large figure of three bright stars, is now sliding down into the western sky. In early October the star Deneb is almost overhead at the apex of the triangle. Deneb is one of the most-distant stars we can see with the naked eye. It is a very luminous star, shining perhaps as much as 200,000 times as bright as our sun. The light from it has taken almost 2,000 years to get here.
In the northwest, the Big Dipper is low in the sky almost skimming the horizon. Follow the arc of the handle of the dipper to the left to the bright orange star Arcturus, a star 10 billion years old, twice the age of our sun.
Find the ‘Lonely Star’
Low in the northeast, the bright star Capella is furiously twinkling because we are looking at it through so much of our atmosphere. Capella is actually four stars in one, two sets of pairs all orbiting each other. Higher in the northeast, a distinctive “W” of stars on end make up the constellation of Cassiopeia the beautiful but boastful queen. Most of the constellations were placed in the sky because of good deeds their characters had performed on earth. Cassiopeia, however, was not liked by the gods and she was placed in an orbit so that she would hang upside down at times, not a very dignified pose for a queen.
Low in the south, a lone star shines forlornly in an area devoid of bright stars. Sometimes called the “Lonely Star,” its strange name Fomalhaut means the “mouth of the fish.” It is the brightest star in Piscis Austrinus, the southern fish, and is a star known to have planets circling it.
If you stay up late enough you might see everyone’s favorite celestial attraction rising in the east, the Pleiades star cluster. Only five or six in the group are visible to the naked eye, depending on your eyesight, but many more will pop into view with the help of binoculars.
October is a great month to view the seldom-seen Zodiacal Light. On a moonless night, look for a broad pyramid of dim light extending above the western horizon just after it gets fully dark. It can also be seen in the east before dawn. What you are seeing are dust particles trapped by gravity in our solar system being back-lit by the sun.
You might catch a glimpse of Mars and maybe Saturn low in the west in early October just after sunset. The pair, which have been with us all summer, are now fading into the sun’s glare. Brilliant Venus will become easier to see in the sunset sky as her orbit brings her into view this fall and winter.