As the summer night sky draws near its close, there are still some cosmic objects that may beckon skywatchers equipped with a small telescope, binoculars or their own two eyes.
Compiling such a list is, of course, very subjective, but here (with apologies to David Letterman) is my own "Top 10" list of summer sky objects to try and catch before they're gone. They are listed in ascending order of merit from this seasoned stargazer:
10) The Cowboy Boot
It's a fact: Thumb through most astronomy books or skywatching guides and you'll find all the accolades going to the most brilliant and splashy star patterns such as Orion, the Hunter, Scorpius, the Scorpion or (for southern observers), the region around Crux, the Southern Cross.
But while the small, faint star patterns usually get short shrift, there's one pattern I always look for, partly because it serves as an excellent gage for determining the quality of the night sky and also because it serves as a "pointer" to one of the summer's best deep-sky objects.
It's nicknamed the Cowboy Boot. This sky map shows where to look for it.
This star arrangement appears in the constellation Vulpecula, the Little Fox, which on most charts seems to be nothing more than a formless splattering of dim stars. But astronomer Hugh Rice, who more than a half century ago used to work at New York's Hayden Planetarium, showed part of this group - on his star maps - resembled a cowboy boot.
The boot even boasted a spur that many cowboys wear.
9) The Dumbbell
Sighted in wide-field binoculars or a telescope's viewfinder, Rice's cowboy boot pattern helps us locate the beautiful Dumbbell nebula (M27). Picked up with very low power as a glowing bubble encompassing two hazy patches of light; it assumes a dumbbell appearance in larger telescopes.
The name "Dumbbell" was, in fact, derived from the description by the Rev. T.W. Webb (1807-1885) of "two hazy masses in contact." And while you're scanning in this area of the sky, be sure to also look for the Arrow (Sagitta) and Job's Coffin, a lozenge-shape pattern of four stars that represents Delphinus, the Dolphin.
8) A Ghostly Doughnut
The little constellation of Lyra is supposed to represent Apollo's harp. Six fainter stars form a little geometric pattern of a parallelogram attached at its northern corner to an equal-sided triangle. Vega gleams at the western part of the triangle. But tucked in this region is the acclaimed Ring nebula.
The two lowest stars in the parallelogram are Beta and Gamma Lyrae. Beta is sometimes also known as Sheliak. Between these two stars, but a trifle nearer to Gamma, is where you will find the Ring nebula.
This sky map shows the location of the Ring nebula in the Lyra constellation.
The nebula shines at magnitude +8.8, and thus is far too faint to be seen with the unaided eye. Any good pair of binoculars will locate it, though it will look almost star-like in appearance because of its small apparent diameter.
The ring shape might just begin to become evident to most eyes in small telescopes using a magnification of 100-power, although at least a 6-inch telescope is recommended to see the ring clearly. With larger instruments and higher magnifications, the ring appears distinctly as a "tiny ghostly doughnut."
7) Draco the Dragon
While most folks are familiar with the Big and Little Dipper, in the same region of the sky is a long, winding group of stars which portrays the mythological creature of a dragon named Draco, which during late evening hours is riding high above Polaris, the North Star.
This sky map shows the location of the constellation Draco in early September.
Draco is a very ancient star grouping. The earliest Sumerians considered these stars to represent the dragon Tiamat. Later it became one of the creatures that Hercules killed. One of Draco's tasks was to guard the garden of Hesperides and its golden apples that Hercules was supposed to retrieve. In the stars, Draco coils around Polaris and we now see Hercules standing (albeit upside down) on Draco's head.
The Dragon's head is the most conspicuous part of Draco: an irregular quadrangle, not quite half the size of the Big Dipper's bowl. The brightest star is Eltanin, a second magnitude star, shining with an orange tinge. Interestingly, a number of temples in Ancient Egypt were oriented toward this star.
The faintest of the four stars in the quadrangle, however, is worth looking for: Nu Draconis, a wonderful double-star for very small telescopes. The two stars are practically the same brightness, both appearing just a trifle brighter than fifth magnitude and separated by just over one arc minute (or about 1/30th the apparent diameter of a full moon).
6) The "Double-Double" Star
Back to the constellation of Lyra once again, this time for a look at another double-star. In fact, you could almost call this one "Nu Draconis squared."
Epsilon Lyrae is better known as the "double-double" star. Exceptionally good vision on a clear, dark night will reveal Epsilon as undoubtedly two tiny stars (designated Epsilon 1 and Epsilon 2) that are very close together.
The separation is approximately one-ninth the apparent diameter of the full moon. This feat is probably right at the limit of perfect vision.
Binoculars will make the two stars clearly visible. But if you train a small telescope on them, then each of these two stars are themselves shown to be double-stars.
So here, in what initially might appear as a single speck of light in the sky, we have a system of four stars, revolving intricately about each other. The two stars that make up Epsilon 1 take at least several hundred years or more to orbit each other. An even longer interval of nearly a thousand years has been assigned to the two stars that make up Epsilon 2.
Meanwhile, both pairs of stars appear to be revolving about each other and have a common center of gravity with a period that probably is on the order of a million years or more,
5) The Wild Ducks
Several clouds of stars surrounded by a few dark regions for contrast can be seen with binoculars in the bright area of the Milky Way about halfway between the star Altair and the constellation of Sagittarius.
Four faint stars in a stretched-out diamond are about all that is visible of Scutum, the Shield. One of the Milky Way's great star clouds is also within Scutum.
Near the northern star of the Shield is the 11th entry in Charles Messier's famous catalogue of "fuzzy" objects masquerading as comets. Messier 11 is one of the richest and most compact of galactic clusters, described by one experienced observer as resembling "a flight of wild ducks."
4) A Cosmic Chrysanthemum
Quite possibly the most celebrated object in the summertime skies is the Great Cluster in Hercules, known also as M13. Anyone who has visited the summer gathering of amateur astronomers near Springfield, Vt., known as Stellafane, know that this famous cluster is often on display in the observatory that houses the famed Porter turret telescope.
To locate M13, look toward the four stars, known as the "Keystone," which supposedly forms the body of Hercules. It's between the two western stars of the keystone that we can find the Great Globular Cluster of Hercules about a third of the way along a line drawn from the stars Eta to Zeta.
This sky map shows the cluster's approximate position.
Actually, it was not Messier, but Sir Edmund Halley (of comet fame), who first mentioned it in 1715, having discovered it the previous year: "This is but a little Patch," he wrote, "but it shows itself to the naked Eye, when the Sky is serene and the Moon absent."
Located at a distance of about 25,000 light years, the Hercules Cluster has been estimated to be a ball of tens of thousands of stars roughly 160 light years in diameter.
If you use good binoculars and look toward that spot in the sky where M13 is you likely will see a similar view: a roundish glow or patch of light. Moving up to a telescope, the view dramatically improves. With a 4 to 6-inch telescope, the "patch" starts to become resolved into hundreds of tiny pinpoints of light. In larger instruments, M13 is transformed into a spectacular celestial chrysanthemum
3) The Coat Hanger
Most amateur astronomers have heard of such beautiful open star clusters as the Pleiades, Hyades and the Beehive. Yet few have ever heard of the "Coat Hanger."
But if you turn your binoculars to the region of the sky roughly halfway between the bright stars Vega and Altair, you will discover this intriguing group of stars. It is not too far away from the Cowboy Boot of Vulpecula that was number 9 on our list.
This sky map shows the Coat Hanger's position in relation to other nearby sky targets.
For some reason that I have never been able to fathom, the Coat hanger Cluster is rarely mentioned, if at all, in most popular astronomy books. Yet, it is the brightest of all the star clusters in this part of the sky!
However, it only appears as a proper coat hanger only for Southern Hemisphere observers, where it appears right side up. In a clear, dark sky you might even perceive it with the naked eye as a fuzzy patch of light. This is one object best suited for your binoculars; even a small telescope with low power will provide too much magnification and will cause the stars to appear too widely spaced apart.
2) Albireo: Blue and Gold
Without question, this is one of — if not the most beautiful — double-stars in the night sky. Located in the constellation of Cygnus, the Swan, Albireo supposedly marks the swan's beak.
A small telescope or even a pair of steadily held binoculars will readily split Albireo into two tiny points of light of beautiful contrasting colors: the brighter one a rich yellowish-orange, the other a deep azure blue, both placed very close together.
An absolutely stunning view will come with a telescope magnifying between 18 and 30 power. Albireo is believed by astronomers to be a physical pair, although there has never been evidence of any orbital motion between these two colorful stars. The projected separation between the two is just over 400 billion miles. At least 55 of our solar systems could be lined-up edge-to-edge, across the space that separates the components of this famous double star.
1) Our Milky Way Galaxy
Summertime is undoubtedly the best time to observe the beautiful Milky Way. With a good pair of binoculars or a telescope you can now observe millions of sparkling little stars that make up this glowing, irregular belt of luminosity.
On early summer evenings it appears to arch from the north-northeast to the south-southeast, with its brightest and most spectacular region running across the Summer Triangle and beyond toward the south-southeast horizon.
There appears to be a great black rift dividing it into two streams, beginning with Cygnus and extending down toward the south. Also in Cygnus is the black void known as the Northern Coal Sack. This Coal Sack and the Rift are not holes in the Milky Way, but rather are vast clouds of dust "floating" out in interstellar space which present a solid and impenetrable curtain between us and the more distant stars.
Never visible from large cities with their bright lights, smoke and haze, the Milky Way can still be readily viewed from distant suburbs and rural locations. Before the invention of the telescope, the true nature of the Milky Way Galaxy ("Gala" is Greek for milk) was a mystery.
The brightest part of the Milky Way is in the constellation of Sagittarius, near the star El Nasl. In fact, this region is roughly our galaxy's center.
Even to the unaided eye, the view is one of excitement and beauty. The Sagittarius Star Cloud, about 30,000 light-years distant, seems to be the nucleus, with the sun and all the outer stars of the galaxy revolving around it at the rate of 155 miles per second. It apparently requires about 200 million of our Earth years to make one complete revolution, or one "cosmic year," around the center of our galaxy.
Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.