A week ago we used Saturn to find the constellation of Sagittarius the archer, better known as the Teapot. Today, we’ll go a bit deeper and explore some of the many deep sky objects you can see there with a pair of binoculars. The term deep sky object (DSO) refers to anything other than stars and planets. Things like galaxies, star clusters and nebulae, objects that are often pictured in glorious color in photos taken with the Hubble Space Telescope.
Normal telescopes like the ones you and I can afford also show lots of DSOs but most appear colorless because our eyes are not cameras. They don’t soak up light like a sponge to reveal the subtle colors in these rather faint objects. We see in real time — moment by moment. Trust me, they are no less beautiful in monochrome.
Of course, a big scope will show lots, but you might be surprised how much you can see in binoculars. And there’s no better place for a deep sky baptism than Sagittarius. I selected 10 objects visible in my 10×50 and 8×40 pairs of binoculars from an outer-suburb location with a modest amount of light pollution. You can see the glow of Duluth, Minn. in the bottom half of the photo at top.
Face south around 10:30 p.m. local time in early August (9:30 in mid-August) and find Jupiter, the brilliant “star” off to the southwest. Reach your fist to Jupiter and measure off three fists to its left (east), and you’ll arrive at another bright “star”. That’s Saturn. It lacks the glamor of Jupiter, but it’s still a standout. Focus your binoculars on Saturn until it’s nice and sharp and then use the photo map above to guide you to each labeled cluster and nebula.
Some have really cool names like the Eagle, Swan and Lagoon because someone thought they resembled those objects (they do!). Some don’t. But they all are cataloged and named by number. For instance, the Lagoon is also called M8 because it’s the 8th object in a catalog created by 18th century French astronomer Charles Messier. The Trifid Nebula — a gorgeous, glowing gas cloud divided into three parts by narrow lanes of light-absorbent cosmic dust — also goes by M20. I like Trifid better.
On the other hand, M25, a bright star cluster, is just M25. Don’t take as a sign of its anonymity. It’s one pretty splash of stars in the 10x50s. One of our featured DSOs is the Small Sagittarius Starcloud, an absolutely stunning binoculars sight from a dark sky. It looks like an island made of stars afloat in the Milky Way. You gotta see it. The Cloud spans about 1½° to the eye, but its real diameter is 600 light years. When you examine it the next clear night try to picture it within the Sagittarius spiral arm, the next galactic spiral arm in from our own, some 10,000 light years in the distance. Wow!
The Lagoon Nebula is probably the biggest, brightest and easiest object to see after the Cloud. It’s a billowing cloud of gas and dust about three times the apparent size of the full moon. Within its corridors new stars are being born. Powerful ultraviolet light streaming from those newborns make the gases glow. You can even see the lagoon itself which looks like a dark lane slicing the object in two halves.
The Trifid is a smudge. The Swan (M17) a bigger smudge, brighter and slightly elongated east-west near its south end. The Eagle (M16) is a small glowing patch with stars dangling below it. And by the way, I cheated a bit on this one — it’s actually in Serpens just over the border from Sagittarius. M22, a globular cluster and a magnificent sight in a telescope, is a tight, round fuzzball with a brighter center. Nearby M28 is the faintest object and may require an extra hard look. It’s also a globular cluster and looks like a faint, out-of-focus star.
M18 is a small fuzzy spot. M25 is splendid star cluster with a line of brighter members easily visible across its core. M23 is one of my favorites — a glowing splotch that looks grainy or granulated. The “grains” are faint stars that are just barely visible and impart a delicate ghostlyness to the object, similar to how parts of the Milky Way look to the unaided eye and for the same reason.
The best time to view our pack of 10 DSOs is at the end of evening twilight when the sky first gets dark and before the returning moon gets too bright. Don’t worry too much about the size of your binoculars. Even the smallest will show a handful of these goodies. Good luck and clear skies!