Similar to a column I wrote a little over a year ago, almost directly overhead at 9 p.m., the constellation of Cygnus, the Swan, is located right in the middle of the Milky Way with it’s head pointing south just like a bird on its autumn migratory flight path.
In the accompanying diagram, it is easy to see how observers equated Cygnus with a swan since the bird’s neck, body, tail and wings are quite evident.
Although supposed to represent one of several mythological individuals, Cygnus is best recognized as a huge celestial cross that is the northern hemisphere’s answer to the constellation Crux, the Southern Cross.
Visible to viewers in our vicinity, Cygnus is visible from June to December and at this time of year, Cygnus lies directly overhead and is almost completely immersed in the faint light of the Milky Way that currently stretches from north-northeast to south-southwest.
Observers in the metro area have an extremely difficult time trying to observe the Milky Way because of the great amount of skylight being generated by all the metro illumination.
The brightest star in Cygnus is named Deneb (Alpha Cygni) and is the last star in the tail of the swan. The name Deneb is derived from the ancient Arabic term dhanab meaning “tail”, hence the nickname tail star in astronomy.
Deneb is a tremendous star estimated to be 25 times the size of our parent Sun and 60,000 times more luminous. As is true with many other bright stars, we are fortunate they are located at such a far distance that the light and heat doesn’t have an effect on Earth.
With the millions of stars overhead, it is easy for us to understand how ancient cultures could have believed each of those stars was equi-distance from us and affixed to a kind of celestial sphere.
As I mentioned above, Cygnus lies right in the middle of the Milky Way and, again, it’s a shame to say that the bright lights in our cities have all but taken away being able to view this tremendous collection of stars.
Perhaps my readers will be interested to know that some of our early Indian cultures were very much aware of the Milky Way and concocted stories about it.
The North American Cherokee viewed the starry “river” as a trail of cornmeal spilled from the mouth of a godlike dog that was coming to steal grain, until villagers scared it off with their drums.
The Florida Seminoles, however, saw it as a path leading to heaven — not unlike the Norse tale that viewed the Milky Way as the road to their afterlife in Valhalla.
If you are blessed with very dark skies you may notice that the Milky Way appears to divide into two streams of stars. There is no actual separation but just tremendous clouds of dark space matter that forms a curtain effectively hiding the more distant stars that lie behind it.
There is a unique star in Cygnus that I and many other astronomers regard as the heaven’s most beautiful. The star is named Alberio and marks the location of the swan’s beak.
To the naked eye, this star looks like a single star when it reality it is a double star in which one star is a deep golden yellow while the other sitting right next to it is a very deep blue. It is really a beautiful and unusual sight and one that always generates “oohs” and “aahs” from first time observers at some of our star parties.