The Milky Way Band: A Guide to the River of Stars
by Sam Atkins
NOTE: Tap or hover over images for captions and credits.
Summer has begun! That means hot days and short nights. While this season comes with its share of nuisances for backyard astronomers (late sunsets, humidity and mosquitoes being chief among them), it also brings a very wonderful silver lining, quite literally. On a clear night, go out to a secluded area far from the city lights and you will see what looks like a sparkling river of stars splashed across the darkness of the cosmos.
This diffuse, glowing streak is the Milky Way band. For countless generations, it stirred the imaginations of ancient people. Civilizations around the world developed mythologies around it that reflected their values and culture. For example, the ancient Greeks described it as spilled milk from Hera after being tricked by Zeus into nursing his son, Heracles. The Chinese told a story of secret, star-crossed lovers separated by the Silver River. Many Native-American tribes saw the Milky Way as a celestial pathway for the departed to reach the spirit world.
It wasn’t until 1610, when Galileo trained his refractor telescope on it that we got a sense of what this bright nebulosity really was. It was made of stars. More than you could ever count. So numerous and distant were they that you couldn’t hope to resolve individual stars without telescopic aid.
The Milky Way Galaxy
The Milky Way band is the dense, star-filled plane of our galaxy, seen edge-on. I say edge-on because the Milky Way is a spiral galaxy, a vast, rotating disk of stars, gas, and dust with graceful arms winding out from a bright central core. Our Sun is just one star among billions in this galaxy, occupying the inner edge of the Orion-Cygnus Arm (one of the minor arms) about 27,000 light years from the galactic core. When you look at the Milky Way band, you are looking through the disk from within the disk. The band actually spans all the way around in a full circle but varies in density depending on the direction. In the winter, the Earth’s position around the Sun puts its night side towards the edge of the galaxy, where the band is thinnest. In the summer, Earth is on the opposite side of the Sun where the night side of Earth is facing towards the galactic center of the Milky Way. This is where the stars and dust are thickest, so much so that the stars seem to blend into a soft, milky haze (hence the name).
The Milky Way galaxy is gargantuan compared to our solar system. As a point of comparison, the distance between the Sun and Neptune, the outermost planet in the solar system, is about 4.5 billion km. That is an incredible distance to us here on Earth. However, the diameter of the Milky Way is 100,000 light-years, meaning it takes 100,000 years to cross the galaxy at the speed of light.
How far would everything be if you shrank the distance between Neptune and the Sun down to the width of a quarter?
The furthest spacecraft from Earth, Voyager 1, would have travelled less than half a foot.
The next closest star, Proxima Centauri, would be more than two football fields away (including the end zones).
The Orion Nebula would be 44.5 miles away.
The entire Milky Way galaxy would be the size of North America.
The Milky Way contains at least 100 billion stars but as many as 400 billion. In our local interstellar neighborhood, the average distance between stars is 4-5 light years (700-875 feet). This makes the aforementioned Proxima Centauri pretty typical. In the galactic core, however, it’s way more crowded with an average distance of 0.1-0.2 light years (17-35 feet).
When and From Where to Look
So when and where can you view the Milky Way band? As said before, while you can technically view the Milky Way band at anytime of the year, you’ll get the best show in the summer. The brightest and most detailed region of the Milky Way is the center and the center is most visible in the night sky during the months of June through August. The galactic center which lies between the zodiac constellations, Sagittarius and Scorpius, is most opposite the Sun in early July (usually around the 4th) and it will spend the most time above the horizon. Waiting for summer is also recommended because seeing it is often not a simple case of walking out of your house and looking up.
The modern world has made the galaxy invisible from the skies over our bright cities and suburbs. From the streets of Baltimore, only the brightest stars in the night sky stand out, like Arcturus and Vega. Fainter stars like those in the Big Dipper or Orion’s belt will too be visible but more challenging. Anything dimmer will be washed out in the skyglow of the city’s buildings, billboards and countless streetlights. Things are much improved in a suburban setting like Bel Air. All the major stars of the constellations should be visible. However, this still won’t be dark enough to see the Milky Way band. You will likely need to make a special trip out of town catch this show. Trust me, it’s worth it.
Life happens, so dropping everything and driving across state lines isn’t going to be an option for everyone all the time. Those with limited opportunity and willing to settle for a compromised view should go to the more rural areas in the northern half of Harford County. The lights of Bel Air and Baltimore still glow on the south and southwestern horizon but on a clear night, this area can provide faint glimpses of the Milky Way band. Members of the Harford County Astronomical Society have special access to the Broad Creek Memorial Scout Reservation at the northeastern-most corner of the county. On the campgrounds is our special “dark site” known as Astronomy Hill. If that sounds really cool, ahem: Contact 2 — Harford County Astronomical Society, Inc.
For more fortunate individuals with a clearer schedule, there are a number of great locations beyond Harford County. For the best possible view of the Milky Way band, consider Cherry Springs State Park in northern Pennsylvania. It’s about a four and a half hour drive from Bel Air but is one of the darkest places on the east coast. Its remote location within the 262,000-acre Susquehannock State Forest offers exceptional 360° views of the night sky where you’ll be able to see thousands of stars with the naked eye.
There are other sites that are a bit closer than Cherry Springs that still offer much better skies than Harford County. South of Ocean City is Assateague Island which is about a three hour drive from Harford County. It offers a good view of the Milky Way accented by the hypnotic metronome of waves on the beach and wild horses grazing on tall grass. In the opposite direction, you get a similar drive time to Greenridge State Forest in western Maryland. It’s the largest contiguous block of public land in the state. Even closer is Tuckahoe State Park which straddles Caroline and Queen Anne’s County on Maryland’s Eastern Shore. This cuts your drive time down to an hour and a half.
Another thing you absolutely must plan around is the lunar cycle. There’s not really a point in driving several hours to a dark site if the moon is going to be washing out the stars all night. If you’re planning a trip, make sure it is as close to the new moon as possible.
You’ll likely be committing some time to this viewing experience so you’ll want to bring some things for maximum enjoyment: a pair of binoculars or a telescope to admire the gorgeous details of the Milky Way band, a red-filtered flashlight to preserve your night vision, a comfortable fold-up chair so you can look up in comfort, and some snacks and drinks.
Basic Observations
You’ve arrived at your chosen destination and are finally feasting your eyes on the starry heavens. What should you be looking for?
Before honing in on the finer details, I would highly recommend letting your first experience remain unstructured. Look at the bigger picture. Before you lies the immense depths of our home galaxy in all its ethereal splendor. Let your eyes wander for a while. Sit back, relax and take it all in.
Far from the bright haze of cities, the night sky comes alive. Where once a few dozen stars quietly marked an opaque background, thousands upon thousands of stars crackle with life. Here, you can see the true diversity of the galaxy’s stellar population. Some stars are brighter while many are dimmer. Some are red or yellow while most are white or blue. Some appear to bundle together in clusters, while others seem to be going their own way.
Periodically, a beam of light will zip across the sky, gone before your eyes can even chase it. These are meteors, often called shooting stars. They’re tiny fragments of rock or dust from space, plunging into Earth’s atmosphere at tremendous speed. The friction superheats the air, causing them to burn up in a brief, brilliant streak. Rare from city streets, they’re common out here beneath dark skies.
The Milky Way band itself appears anchored to the southern horizon, tilted eastward after sunset. As night deepens, it arcs westward like the hand of a clock. Under dark skies, it presents as a broad, diffuse glow stretching across the heavens, the combined light of countless unresolved stars, shaped by interstellar dust and gas. The band’s brightness varies: some regions shine with dense stellar concentrations, while others are dimmed or obscured by dark nebulae, cold molecular clouds that block starlight. In fact, there appears to be a long dark lane that cuts right through the middle of the Milky Way band, known as the Great Rift. This is a stream of cosmic dust that lies between our solar system and the next inward spiral arm, the Sagittarius Arm.
Once your eyes have fully adjusted and you’ve taken in the view, let’s look closer. Whether you continue on with the naked eye or want to switch to your scope or binos is up to you. Let’s start close to the horizon and work our way up the Milky Way band (we will assume you are at a latitude of or close to 40° north).
Sagittarius & Scorpius: The Heart of the Milky Way
Just over the southern horizon, we begin with two grand constellations flanking the densest stretch of the Milky Way band. The region between them marks the center of our galaxy.
Note: In the diagrams below, blue regions represent bright star-filled regions while white regions are obscured by dust and gas. Yellow or blue dashed lines represent constellation boundaries while the red-dashed line is the ecliptic (Earth’s orbital path around the Sun).
On the east side of the Milky Way band, look for a teapot-shaped asterism rising over the horizon. This makes up the main body of Sagittarius the Archer. This region of sky is crowded with beautiful deep-sky objects as well. Within and immediately around the teapot are a handful of well-defined globular clusters (M22, M28, M54, M69 and M70).
The “spout” of the teapot seems to pour directly into a very bright milky haze to the west. This is the Large Sagittarius Star Cloud which is part of the Sagittarius Arm, another minor arm. It is the brightest region of the entire Milky Way band, containing so many stars that even binoculars will struggle to resolve individual ones. These stars are likely around 4-5,000 light years away. Lurking deep beyond this bright region is Sagittarius A* (pronounced “A star”). This supermassive blackhole lies 27,000 light years away in the very heart of the Milky Way and is that which everything else in our galaxy revolves around, including our solar system. It is estimated to have a mass of at least 4 million times that of the Sun.
Congregating northwest of the teapot is a small but exquisite assortment of nebulae and open clusters. This includes the sizable Lagoon Nebula (M8), as well as its upstairs neighbors, the Trifid Nebula (M20), and the M21 open cluster. These objects provide a good bit of color to the region. Directly north of the teapot is another particularly bright and pale patch of sky called the Small Sagittarius Star Cloud (M24). This region spanning 600 light-years across is a continuation of the Sagittarius Arm through a break in the dark cosmic dust.
To the west of the Milky Way band, look for an orange star that outshines all around it. This is Antares, a red supergiant at the heart of Scorpius. To the west of Antares, you will find a row of three seemingly-identical bluish stars collectively dubbed the Scorpion’s Crown. Don’t let their simple appearance fool you. These are complex multi-star systems. You will find a couple of beautiful globular clusters between Antares and the Scorpion’s Crown (M4 and M80).
Scorpius’ body extends down from Antares towards the horizon before curling eastward into the Milky Way band. Right at the start of this curl, you’ll find a loose star cluster called the Northern Jewel Box (NGC 6231). If you follow all the way around to the curled-end of the scorpion’s tail, you’ll end up near two more beautiful and robust star clusters. Northeast of the stinger is Ptolemy Cluster (M7), one of the oldest and most prominent star clusters known in the night sky. About 5° to the northwest is the Butterfly Cluster (M6), which takes the form of its namesake.
Scutum & Serpens: Climbing Higher
From the Milky Way center, let your gaze follow up the galactic plane where you’ll find a clash between light and dark.
On the east side of the Milky Way band, the same side as Sagittarius, you’ll find Scutum the Shield.
The stars of the Scutum constellation are not particularly bright. Only two of them reach 4th magnitude. However, the backdrop of the Milky Way band here is plenty bright enough to illuminate this shield with starlight. The Great Scutum Star Cloud lies in the northern half of the constellation (the blue region above). Through a scope or pair of binoculars, it looks like a sea of stars.
At the northern border of the Great Scutum Star Cloud is an unusually dense open cluster called the Wild Duck Cluster (M11). It is one of the richest and most compact of its kind and the most distant star cluster in the Messier catalogue visible to the naked eye. About 2.5° to the south, is a small globular cluster called NGC 6712. About 2° to the west of that, towards the center of Scutum is M26, an open cluster.
To the southwest of Scutum, you can find three patches of nebulae in a line. The southernmost is the Omega Nebula (M17), one of the largest stellar nurseries in the Milky Way. The middle one is the Eagle Nebula (M16) which is most known as the site of the famous Hubble image of the “Pillars of Creation.” While you won’t get remotely the same detail as Hubble did, you should be able to resolve the shape of these three towers of gas and dust. The northern one is Sh 2-54, another emission nebula. All three are believed to be a part of the Sagittarius Arm.
On the west side of the Milky Way band, the same side as Scorpius, you’ll find Serpens the Serpent.
Serpens is unique amongst constellations in that it is the only one separated into two non-contiguous parts. This is due to the serpent being wrapped around the large equatorial constellation, Ophiuchus. While this snake-bearing healer lies above the galactic plane, the tail end of the snake, known as Serpens Cauda, moves right through it. Like Scutum, Serpens Cauda is not a particularly flashy constellation but is rather defined here by how it contrasts against its backdrop. While Scutum shines in the ethereal starlight of the Sagittarius Arm, Serpens slithers through the darkest patch of sky in the entire Milky Way band, the Serpens-Aquila Rift which is part of the larger Great Rift.
Aquila & Cygnus: Wings Across the Summer Triangle
As the Milky Way arches high overhead, an eagle and swan soar along the river of stars through summer’s brightest triad.
While following up the Milky Way band from Scutum, you will pass along a dark lane called the Great Rift, a massive network of interstellar clouds that obscure the sea of background stars of the Sagittarius Arm.
The easiest way to navigate the next region of the Milky Way band is by locating the Summer Triangle, a simple but large asterism consisting of three eye-catching stars. Together they form the triangle being intersected by the galactic plane. Each of these stars are the brightest of their respective constellations: Altair in Aquila, Deneb in Cygnus and Vega in Lyra. While Altair and Vega appear brighter, this is pretty much entirely due to their close proximity to Earth (16 and 25 light years, respectively). Deneb is by no means faint but certainly the dimmer than the other two. This is deceiving because, in reality, Deneb is actually thousands of times more luminous but is also possibly thousands of light years away.
Let’s hone in on Altair, the southernmost star of the Summer Triangle and the twelfth brightest star in the night sky. Altair acts as a lighthouse to find Aquila, a constellation in the shape of an eagle. Its wings spread 20° across from north to south, with one overlapping with the Great Rift. If you came prepared to do some astrophotography, there are a handful of small planetary nebulae found in this region, particularly around the southwestern quadrant (between the stars marked λ, δ, and ζ). If you are just doing some simple sightseeing, I would seek out the lonely star cluster NGC 6709. It is located about 5° to the southwest of Zeta Aquila (marked with a ζ).
Located between Aquila and Cygnus, in the center of the Summer Triangle, are two small constellations: Sagitta the Arrow and Vulpecula the Little Fox. Here you can find some fun deep sky objects!
The M71 globular cluster can be found halfway between the stars, Gamma Sagittae (marked with a γ) and Delta Sagittae.
The Dumbbell Nebula (M27) can be found two-fifths of the way between the stars, Gamma Sagittae (marked with a γ) and 15 Vulpeculae.
The Coathanger asterism can be found a third of the way between the stars, Altair and Vega.
Continuing northward from Aquila and you’ll reach a large constellation that looks like a cross. This is Cygnus the Swan which has an even more impressive north-south wingspan almost double the length of Aquila’s. It is sometimes referred to as the Northern Cross. Cygnus is quite a busy cosmic region compared to Aquila. While the background is flooded with darkness as the Great Rift begins to unravel, Cygnus is packed with various types of nebulae (emission, planetary, and dark nebulae) and a handful of open star clusters.
I would start at the head of the swan, a star named Albireo (marked with a β). Through a pair of binoculars or a small telescope, it is revealed to be one of the finest double stars in the Northern Hemisphere, one gold and one blue. At the heart of Cygnus is a white star named Sadr (marked with a γ). Just past this star is M29, a tight cluster of golden stars. At the far end of the constellation is its brightest star, Deneb, the tail of the swan and one of the vertexes of the Summer Triangle.
If you are doing astrophotography, the North American Nebula (NGC 7000), right next to Deneb, and the Veil Nebula (made up of NGC 6992 and NGC 6960), along the southern wing, are an absolute must see. The former is a sprawling emission nebula while the latter is the wispy and shredded remnants of a supernova. Both of these nebulae are faint to the naked eye but spring to life under long exposure imaging. You also might try the Crescent Nebula near Sadr as well.
As we move beyond Cygnus, you’ll start to notice a drop off in the density of stars along the Milky Way band.
Cepheus & Cassiopeia: Crowns of the Fading North
The Milky Way band softens and frays as you pass the Summer Triangle looming overhead. Here, the outer regions of the galactic plane appears to sink back down towards the northern horizon, which is presided over by two royal figures all year long.
Despite its regal associations, Cepheus the King is a relatively modest constellation, resembling a cone or a house with the pointy end facing the ground. An easy way to find it is by finding the Big Dipper. Trace an imaginary line across the stars making up the outer edge of the cup (from Merak through Dubhe) towards Polaris. Continue past the North Star and you’ll land right on Cepheus. Its brightest component, named Alderamin (marked with an α), is barely a second magnitude star. It will gain more importance in about 5,500 years when the precession of Earth’s axial tilt swings it around to within 3°, effectively making it the future North Star.
This constellation is a great target for astrophotographers. Most notable is a large emission nebula called Trumpler 37 (IC 1396) with a small cluster of young stars embedded in its heart. Long exposure should bring out significant details such as the Elephant Trunk Nebula, a gaseous peninsula near the center. At the edge of Trumpler 37, you’ll notice a lone 4th magnitude star with a deep red hue, known as the Garnet Star. This is one of the largest stars visible to the naked eye. If it were to replace our Sun, its surface would reach beyond the orbit of Jupiter! It is incredibly distant, about as far away as the galactic center. This massive star is expected to go supernova in the next few million years.
Another fun target for astro imaging is NGC 7023, also known as the Iris Nebula. This flowering patch of cosmic gas and dust is lit up by the reflected blue light of the star at its center, located about 1,200 light years from Earth.
Across the galactic plane, to the southeast, you’ll find a constellation of five stars forming a W shape. This is Cassiopeia the Queen, a brighter and more easily recognizable constellation than her male counterpart. While Cepheus is surrounded by hydrogen nebulae that require long exposure imaging, Cassiopeia is studded with dozens of star clusters, many are readily visible through a pair of binoculars or telescope.
One such example is M52, which lies between the two constellations. The easiest way to find it is to trace an imaginary line through the two brightest stars in Cassiopeia (from α to β), and continue on for an additional 6°. Right next to this star cluster is a good astro imaging target, the Bubble Nebula (NGC 7635). Another compact but dense star cluster is M103. This is pretty easy to find as it is located just a degree away from the star, Ruchbah (marked with δ). At least 8,000 light years away, this is one of the most distant open clusters we known of. There is an interesting nebula with a similar orientation to another star in Cassiopeia, Schedar (marked with an α). This is the Pacman Nebula (NGC 281), so named due to its resemblance to the classic video game character.
When you are ready to move on to the finale of this stellar parade, find the central star of Cassiopeia (marked with a γ) and trace an imaginary line through Ruchbah (marked with δ) and continue on. You’ll eventually reach Perseus.
Perseus: A Hero in the Darkness
As our journey across the river of stars reaches the opposite horizon, we meet one final figure before daybreak.
Perseus is the mythical Greek hero who saved Princess Andromeda from the clutches of horrible beasts. This constellation fits him very well. Just as the gods adorned him with powerful armaments, this constellation is adorned with a variety of star clusters and nebulae. However, you’ll have to wait till pre-dawn hours if you want to see it in the summer months. The constellation won’t fully emerge above the northeastern horizon until after 3:00am. The morning Sun will wash out the Milky Way by 4:30am so be ready for a limited window. Otherwise, it might be best to wait until the fall season.
If you are reaching Perseus from Cassiopeia, you likely passed through one of the coolest deep sky objects in the entire night sky, the Double Cluster. Located roughly halfway between the two constellations, this is a large and bright pair of open clusters. The western cluster is NGC 869 and is the more condensed of the two. The eastern cluster is NGC 884 and looks like a shattered version of its companion. This is a marvel to see through a pair of binoculars or a telescope. Both clusters lie 7,500 light years away in the Perseus Arm of the Milky Way.
Moving down to Perseus proper, you’ll find the bright supergiant star at the very center of the constellation, Mirfak (marked with an α). This also marks the center of another open cluster of stars called the Alpha Persei cluster. This loose grouping of stars is relatively close to Earth at just 560 light years away. Following down the eastern side of the constellation we reach the second brightest star in Perseus, Algol. There is a compact open cluster located between this white-blue star and the red star, Almach, in neighboring Andromeda. Trace an imaginary line between the two and you’ll find M34 about 2/5ths of the way.
Let’s cap off this tour with another great target for astrophotographers. From the central star, Mirfak, this time we follow down the western side of Perseus. Right before we arrive at Xi Persei (marked with a ξ) we find the famous California Nebula. This gargantuan streak of hydrogen gas stretches five full moons across. Its actual length is 100 light years long! That’s 20 times the distance between our solar system and the next nearest star, Proxima Centauri. It is suspected that the scorching radiation from Xi Persei is ionizing the gas here and causing it to glow.
Fall Viewing
If you wait until September to observe the Milky Way band, you’ll trade in the glory of the galactic center for a pretty magnificent encore at the end. Here you’ll get to see Perseus showing off in the northeast as early as 9:00pm (instead of 3:00am in the summer). Additionally, the mythic Greek hero will be followed by the winter constellations late into the night. These star patterns hug the outside of the thinnest regions of the Milky Way band, towards the perimeter of the galaxy.
Directly south of Perseus is Auriga the Charioteer, an equally-sizable hexagon-shaped constellation featuring the third brightest star in the northern hemisphere, Capella. It is also the location of the galactic anticenter, the point in space that is directly opposite of the galactic center. It is about 23,000 light years to nearest edge of the galaxy’s main stellar disk.
Continue down further and you reach the point where the galactic plane crosses the ecliptic, which represents Earth’s orbital plane around the Sun. During the summertime, this intersection is around where the Sun is on the first day of summer. Also here, are some of the zodiac constellations, each dipping a small part of themselves into the Milky Way band. The twins of Gemini, quickly identified by their two brightest stars, Castor and Pollux, dip their toes into the eastern side of the Milky Way band. The horns of Taurus the Bull pierce into the western side. Outward from there, you can find the bull’s V-shaped head and the Pleiades cluster above.
Below Taurus you can find arguably the most recognizable constellation there is, Orion the Hunter. He has his club raised above his raised into the Milky Way band as well. Below the three stars of his belt you can find the Orion Nebula, one of the brightest nebulae in the entire night sky. Below Orion, if you look just above the horizon right before the morning glow of the Sun starts to creep across the sky, you can find the luminous and twinkling star, Sirius, in Canis Major. This is the brightest star in the entire night sky due to its 8 light year distance.
For as long as humans have looked to the night sky, the Milky Way has been there, sparking wonder, curiosity and stories. To truly grasp the scale of the galaxy we live in can be sobering. The sky that once likely seemed like a flat, featureless dome around us becomes imbued with profound depth. It becomes multi-dimensional. It provides a humbling sense of vertigo, the awareness that your feet are no longer planted down on the ground with the sky above. There is no ‘up’ or ‘down’ anymore, nor is there truly a ‘left’ or ‘right.’ You and the Earth are drifting untethered in a vast ocean of space and time.