Looking Up: Catch the Double Cluster next clear night
For a real treat, the next clear night, look for the Double Cluster, a pair of rich star clusters nearly in contact. With a dark sky, the Double Cluster is visible as a hazy patch with unaided eyes. They are easily seen with binoculars as two star clusters, and the view in a small telescope is spectacular. They are also easy to find.
On October evenings, the five stars marking the “W”- shaped constellation Cassiopeia the Queen, appear standing almost on its side, high in the north-northeast. Starting from the top star in Cassiopeia, the third segment of the “W” points almost straight down in this orientation. Note the apparent distance between the two stars of this segment, and extend this distance approximately twice as far. This points right at this fuzzy patch. If you don’t see a fuzzy patch, perhaps because there is a little too much light pollution where you are, try binoculars and you should located it fairly quickly. You can start at the two stars in that segment of the “W” and make you way down with binoculars. The clusters are officially known as NGC 869 and NGC 884, which refers to the New General Catalogue (NGC), one of several compendiums of star clusters, galaxies and nebulous objects that astronomers use. They are also listed as Caldwell 14, as well as h Persei and x Persei. Too many names… and the star clusters themselves know nothing of what we Earthlings want to call them! Like Monarch butterflies, red shale rocks and oak trees, names come in handy for our reference.
These clusters are around 7,500 lights years from Earth; that’s how many years it takes for their starlight to reach us, traveling at around 5.88 TRILLION miles a year.
Guess where they are traveling? the Double Cluster is headed in OUR general direction, at about 24 miles a second! There are thousands of stars among this pair, traveling the galaxy together bound by mutual gravitation and we hope, affection! At least we humans are capable of the latter, and sights such as the Double Cluster keep many of us looking up.
Most of their stars are blue-white super-giant stars. With a small telescope, you may spot a few reddish stars in the field of view, although some stars may be just in our line of sight and not connected with the clusters.
Use low magnification with a small telescope, to get both of the clusters in the same field of view.
They are found within the constellation Perseus. From this general area, the famed Perseid meteor shower appears to radiate across our night skies, every August.
If you have a dark sky, enjoy sweeping this whole area in binoculars or a small telescope. The Double Cluster is seen within the Milky Way Band, which is dense with faint stars and star clusters, in an infinite variety of chance arrangements.
New Moon is on October 19. In the pre-dawn sky this week leading up to the 19th, look low in the east for the crescent Moon, as it passes Mars and the much brighter planet Venus. On October 17, the Moon appears right between the planets.
Keep looking up!
— Peter Becker is Managing Editor at The News Eagle in Hawley, PA. Notes are welcome at email@example.com. Please mention in what newspaper or web site you read this column.