Monthly Sky Night Map
Our sky map for October 2016 is a free and printable star chart to see stars and constellations in the night sky, from The Old Farmer’s Almanac.
Four Constellations in a Row
This month, we’ll focus on the very bright star Altair to guide you to four constellations that most sky watchers never notice.
When you look to the southwest in October, the star Altair shines front-and-center. Only 11 stars in the whole sky are brighter than Altair. One of the reasons that Altair is so bright is that it is relatively close to Earth, less than 17 light-years away. That’s still a fantastically great distance, but Altair is closer than most stars we can see with our unaided, or “naked,” eyes.
Altair is a handy signpost that guides us to four small constellations. They are lined up in a neat row just above Altair. All four are notably lacking in bright stars and are best seen during the first and last weeks of October, when the Moon is near first or last quarter.
Equuleus: Starting from the left, we have Equuleus, the Little Horse (or Foal), the second smallest of all constellations. Equuleus is an example of a constellation that bears little resemblance to its namesake. It earned its name solely by virtue of its location near the nose of Pegasus the Winged Horse.
Delphinus: For a constellation that does look like it namesake, look no farther than Delphinus the Dolphin. To my eye, Delphinus most certainly resembles a dolphin leaping upward from the celestial sea.
Sagitta: Next in line is another easily recognized figure. It’s Sagitta the Arrow, the weapon which, in Greek mythology, was used by Hercules to slay Aquila the Eagle. Strangely, Sagitta appears to be flying away from Aquila rather than toward him. We must allow the ancient Greeks a bit of poetic license!
These first three little constellations were envisioned by star gazers thousands of years ago and appear in the list of 48 constellations compiled by the astronomer Ptolemy in the 2nd century. In contrast, Vulpecula the Fox is a more modern invention.
Vulpecula: Astronomer Johannes Hevelius published his own list of constellations in 1687. He included the 48 constellations from Ptolemy’s list but added a few of his own. One of the additions was Vulpecula the Fox, apparently invented to “use up” a few stray stars not otherwise assigned to other constellations.
October 2016 Sky Map
Click here or on image below to enlarge this map (PDF).
Sky map produced using Chris Marriott’s Skymap Pro
And Four More
On nights when moonlight prevents you from seeing the four dim constellations above Altair, there are other, more conspicuous shapes in the October sky.
Vega: Above and to the right of Altair sits Vega, fifth brightest of all stars and part of the constellation Lyra the Lyre. Note the lovely Parallelogram asterism (unofficial star pattern) that comprises the main body of the Lyre.
Hercules: To the right and slightly below Lyra is the Keystone asterism in Hercules, a sprawling constellation representing the Greek hero. The stars of Hercules are difficult to envision as a human figure, but the Keystone stands out clearly.
Corona Borealis: Farther to the right lies Corona Borealis, the Northern Crown. On a dark night, the tiara shape of this constellation forms a near-perfect semicircle.
The Teapot: If your horizon is clear of trees, buildings, and man-made light, you may be able to see the Teapot asterism in Sagittarius the Archer. At this time of year, the Teapot is tipped as if pouring out its contents. The planet Mars glows near the Teapot’s handle.
Enjoy the crisp, clear nights of October and try to glimpse the four little constellations that dwell above Altair!
Enjoy astronomy? Check out “This Week’s Amazing Sky” column!