The constellations help us find our way around the sky, breaking up the endless array of stars into more manageable and memorable chunks. In this article, I’ll discuss five constellations I always start with and how they guide me to other fascinating astronomical phenomena.
All illustrations of constellations in this article are for demonstration purposes only and are not to scale.
5
Ursa Major
Possibly one of the best-known constellations in the northern sky, Ursa Major—or the Great Bear—contains an asterism of seven stars known as the Big Dipper (or, in other countries, the Plough), which is labeled “1” in the illustration below. It’s the third-largest constellation (behind Virgo and Hydra), but it leads the way as an astronomical pathfinder, offering various deep-sky viewing opportunities that stargazers at all levels can enjoy.
Mizar and Alcor
One of my favorite points in the sky is the double star, Mizar and Alcor, located in the Big Dipper asterism.
The reason I love it so much is that it’s hidden in plain sight—many of us have spent quite some time observing the well-known constellation, but significantly fewer of us realize that there are two stars sitting apparently beside each other. Mizar and Alcor are visible to the naked eye, but you’ll fully appreciate their distinction if viewed with binoculars.
M81 (Bode’s Galaxy)
Just above the Bear’s shoulders, use your binoculars to spot M81, a fuzzy-looking galaxy 12 million light-years away. It’s the closest galaxy to Earth outside our local group, and if you look for long enough, you’ll also spot its neighbor galaxy, M82, to the north. Amazingly, these two galaxies are in conflict, with M82 showing signs of gravitational scarring in close-up images.
Ursa Minor and Polaris
One of the first star-hopping journeys I made when I started appreciating Ursa Major was to Ursa Minor (the Little Bear). Start by drawing an imaginary line between the two outer stars in the Big Dipper’s “Bowl” (known as The Pointers), and continue this line until you reach Polaris.
Since Polaris is the North Pole Star, it represents the end of Earth’s axial line, meaning it stays visually stationary in the sky. It’s certainly not the brightest star in the sky, but each time you draw that imaginary line, it becomes easier to locate.
Boötes and Virgo
Moving back to the Big Dipper, follow the stars back through the bowl and towards Mizar and Alcor, the double star I talked about earlier. Then, continue the slightly curved line away from the Big Dipper to the next brightest star—and the fourth-brightest star in the night sky—Arcturus (labeled “1” below), which is the leading star of the Boötes constellation. Carry on further to find Spica (labeled “2” below), the blue, main star of Virgo.
Leo and Gemini
The final two paths take us underneath the Big Dipper to Leo and Gemini.
Leo is directly beneath the Big Dipper, beyond the smaller Leo Minor constellation, and is host to Regulus (labeled “1” below), its primary star. Gemini’s head stars, Castor and Pollux (labeled “2” below), stand out in the sky due to their brightness.
4
Cassiopeia
Cassiopeia is one of the proudest constellations in the sky and stands out for its distinctive W- or M-shaped formation. It never drops below the Northern Hemisphere sky’s horizon, so it’s a great go-to and a brilliant locator for other important celestial features.
The Milky Way
Have you ever looked up and wondered whether that faint white band across the sky is wispy clouds or the Milky Way galaxy? Well, since Cassiopeia sits right in the center of the Milky Way streak that we can see from Earth, it’s a good way to determine exactly what you’re looking at.
Once you have determined that it is, indeed, the Milky Way you’re looking at, take a moment to appreciate its magnificence. Our galaxy is truly massive, a wheel-shaped spiral of nebulae and stars. When we look up, we’re casting our gaze across the wheel, which is the perspective from which those nebulae and stars are at their densest. You’ll appreciate this even more if you’re armed with a pair of binoculars in a dark-sky area.
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Cygnus
A natural pathfinding jump is from Cassiopeia to Cygnus because they both run along the Milky Way band I talked about earlier. Follow this band from Cassiopeia and through Cepheus to the majestically recognizable Cygnus, also known as the Northern Cross.
Deneb (labeled “1” above) is Cygnus’ best-known star and the first point of light when you locate the constellation from Cassiopeia. Amazingly, even though it appears dimmer than many other major stars in the sky, Deneb’s numbers are breathtaking—it’s 1,500 light-years away, 60,000 times brighter than the Sun, and is around 300 times our star’s diameter!
Vega
Beneath the right wing of Cygnus is the constellation Lyra, whose main star is Vega (labeled “1” in the illustration below), the fifth-brightest star in the night sky and one that always jumps out. It’s one of the most studied stars of all, primarily because it’s surrounded by a dusty halo that is said to be similar to our solar system’s Kuiper Belt. The fact that recent observations by the James Webb Space Telescope failed to find any evidence of planets leaves scientists wondering exactly what makes up the ring of debris.
2
Pegasus
Pegasus is said to resemble the shape of a horse with wings and is next to the much fainter Pisces constellation. The beauty of this area of the sky is that it’s relatively quiet compared to other areas. This makes locating Pegasus and its nearby phenomena easier than in other parts of our stellar tapestry.
First, head back to Cassiopeia, and extend either of the two down-strokes in the W downwards to encounter a massive square in the sky, the Great Square of Pegasus. This is the body of the Winged Horse.
M31 (The Andromeda Galaxy)
The Great Square of Pegasus is my starting point for finding the Andromeda Galaxy.
Take the corner of the square closest to Cassiopeia (Alpheratz), head away from the square to find Delta Andromedae, and head the same distance again to find Mirach, a red giant star. You’re now well and truly in the Andromeda constellation. Next, take a right-hand turn and travel roughly the same distance one more time to stumble upon a smudge in the sky, the Andromeda Galaxy.
While this might seem quite a complex path to follow, once you’ve done it once, it’ll stay etched in your memory.
The Andromeda Galaxy (M31) can be seen with the naked eye in dark-sky areas as a misty oval patch, and it’s easily identifiable with binoculars, even among outer-city lights. Even though it’s our neighboring galaxy, it’s around 2.5 million light-years away! Incredibly, it’s one of the furthest objects that can be seen without special equipment. If you could see the whole galaxy in detail from Earth, it would be about six Earth Moons wide.
Not-so-fun fact: Approaching each other at 68.4 miles per second, The Milky Way and Andromeda Galaxies are predicted to collide in around 4.5 billion years’ time.
1
Orion
Orion never fails to amaze me. It’s so full of features that you can stand and stare at it for an hour and still discover new things, much like observing a complex painting in the Louvre.
In the Northern Hemisphere, Orion is loud and proud towards the south and can be easily identified due to its impressive features.
Orion’s Belt
The Orion’s Belt asterism (labeled “1” in the illustration above) is the starting point for finding the rest of the Orion constellation. It’s made up of three stars that are almost perfectly aligned, equally spaced, and similarly illuminated.
M42 (The Orion Nebula)
Move south from Orion’s Belt to find the constellation’s nebula (labeled “2” in the diagram above), a true gem of the sky containing vast clouds of dust and gas where stars are actively forming. It’s visible to the naked eye, even in light-polluted areas, and looks like someone has deliberately smudged the sky. Viewed through binoculars, it’s an even more beautiful feature of our nighttime ceiling.
Betelgeuse
Learning how to pronounce this star’s name (“beetle juice”) took me longer than finding the star itself (the main star above the Belt)! I love looking at this red supergiant (labeled “3” in the illustration above) mainly because of its phenomenal properties. It’s an amazing 1,000 times the size of the Sun and 14,700 times brighter. If you replaced our star with this red supergiant, its surface would extend beyond Mars’ orbit.
Make sure you prepare thoroughly before heading outside for a stargazing session: account for the moon phases, check the weather, get away from city lights, and wear comfortable clothes!
