Why buy binoculars for stargazing?
Okay admit it. You’ve probably got a pair of binoculars lying around your house somewhere. They may be perfect – that’s right, perfect – for beginning stargazing.
The fact is that most people who think they want to buy a telescope would be better off using binoculars for awhile instead. That’s because first-time telescope users often find themselves completely confused – and ultimately put off – by the dual tasks of learning the use a complicated piece of equipment (the ‘scope) while at the same time learning to navigate an unknown realm (the night sky).
Beginning stargazers often find that an ordinary pair of binoculars – available from any discount store – can give them the experience they’re looking for. After all, in astronomy, magnification and light-gathering power let you see more of what’s up there. Even a moderate form of power, like those provided by a pair of 7×50 binoculars, reveals 7 times as much information as the unaided eye can see.
So what should you buy? The video below – from ExpertVillage – does a good job summing it up.
And in case you didn’t watch the video, the answer is that 7X50 binoculars are optimum for budding astronomers. You can see a lot, and you can hold them steadily enough that jitters don’t spoil your view of the sky. Plus they’re very useful for daylight pursuits, like birdwatching.
What can I see with binoculars?
If the moon is just past new – and visible as a waxing crescent in the western sky after sunset – you might have a beautiful view of earthshine on the moon. This eerie glow on the moon’s darkened portion is really light reflected from Earth onto the moon’s surface. Be sure to turn your binoculars on the moon at these times to enhance the view. By the way, the image at right is from Dan Bush, whose Missouri Skies Moon Page is not to be missed.
Each month, as the moon goes through its regular phases, you can see the line of sunrise and sunset on the moon progress across the moon’s face. This line between the day and night sides of the moon is called the “terminator line.” The best place to look at the moon from Earth – using your binoculars – is along the terminator line. The sun angle is very low in this twilight zone, just as the sun is low in our sky around earthly twilight. So, along the terminator on the moon, lunar features cast long shadows in sharp relief.
You can also look in on the gray blotches on the moon called “maria”, named when early astronomers thought these lunar features were seas. The maria are not seas, of course, and instead they’re now thought to have formed 3 1/2 billion years ago when asteroid-sized rocks hit the moon so hard that lava percolated up through cracks in the lunar crust and flooded the impact basins. These lava plains cooled and eventually formed the gray seas we see today.
The white highlands, nestled between the maria, are older terrain pockmarked by thousands of craters that formed over the eons. Some of the larger craters are visible in binoculars. One of them, Tycho, at the six o’clock position on the moon, emanates long swatches of white rays for hundreds of miles over the adjacent highlands. This is material kicked out during the Tycho impact 2.5 million years ago.
Planets. Here’s the deal about planets. They move around, apart from the fixed stars. They are “wanderers,” right?
You can use our EarthSky Tonight page to locate planets visible around now. Notice if any planets are mentioned in the calendar on the Tonight page, and if so click on that day’s link. On our Tonight page, we feature planets on days when they’re easily identifiable for some reason – for example, when a planet is near the moon. So our Tonight page calendar can help you come to know the planets, and, as you’re learning to identify them, keep your binoculars very handy. Binoculars will enhance your view of a planet near the moon, for example, or two planets near each other in the twilight sky. They add a lot to the fun!
Below, you’ll find some more simple ideas on how to view planets with your binoculars.
Mercury and Venus. These are both inner planets. They orbit the sun closer than Earth’s orbit. And for that reason, both Mercury and Venus show phases as seen from Earth at certain times in their orbit – a few days before or after the planet passes between the sun and Earth. At such times, turn your binoculars on Mercury or Venus. Good optical quality helps here, but you should be able to see them in a crescent phase. Tip: Venus is so bright that its glare will overwhelm the view. Try looking in twilight instead of true darkness.
Mars. Mars – the Red Planet – really does look red, and using binoculars will intensify the color of this object (or of any colored star). Mars also moves rapidly in front of the stars, and it’s fun to aim your binoculars in its direction when it’s passing near another bright star or planet.
Jupiter. Now on to the real action! Jupiter is a great binocular target, even for beginners. If you are sure to hold your binoculars steadily as you peer at this bright planet, you should see four bright points of light near it. These are the Galilean Satellites – four moons gleaned through one of the first telescopes ever made, by the Italian astronomer Galileo. Note how their relative positions change from night to night as each moon moves around Jupiter in its own orbit.
Saturn. Although a small telescope is needed to see Saturn’s rings, you can use your binoculars to see Saturn’s beautiful golden color. Experienced observers sometimes glimpse Saturn’s largest moon Titan with binoculars. Also, good-quality high-powered binoculars – mounted on a tripod – will show you that Saturn is not round. The rings give it an elliptical shape.
Uranus and Neptune. Some planets are squarely binocular and telescope targets. If you’re armed with a finder chart, two of them, Uranus and Neptune, are easy to spot in binoculars. Uranus might even look greenish, thanks to methane in the planet’s atmosphere. Once a year, Uranus is barely bright enough to glimpse with the unaided eye . . . use binoculars to find it first. Distant Neptune will always look like a star, even though it has an atmosphere practically identical to Uranus.
There are still other denizens of the solar system you can capture through binocs. Look for the occasional comet, which appears as a fuzzy blob of light. Then there are the asteroids – fully 12 of them can be followed with binoculars when they are at their brightest. Because an asteroid looks star-like, the secret to confirming its presence is to sketch a star field through which it’s passing. Do this over subsequent nights; the star that changes position relative to the others is our solar system interloper.
Inside the Milky Way. Binoculars can introduce you to many members of our home galaxy. A good place to start is with star clusters that are close to Earth. They cover a larger area of the sky than other, more distant clusters usually glimpsed through a telescope.
Beginning each autumn and into the spring, look for a tiny dipper-like cluster of stars called the Pleiades. The cluster – sometimes also called the Seven Sisters – is noticeable for being small yet distinctively dipper-like. While most people say they see only six stars here with the unaided eye, binoculars reveal many more stars, plus a dainty chain of stars extending off to one side. The Pleiades star cluster is looks big and distinctive because it’s relatively close – about 400 light years from Earth. This dipper-shaped cluster is a true cluster of stars in space. Its members were born around the same time and are still bound by gravity. These stars are very young, on the order of 20 million years old, in contrast to the roughly five billion years for our sun.
Stars in a cluster all formed from the same gas cloud. You can also see what the Pleiades might have like in a primordial state, by shifting your gaze to the prominent constellation Orion the Hunter. Look for Orion’s sword stars, just below his prominent belt stars. If the night is crisp and clear, and you’re away from urban streetlight glare, unaided eyes will show that the sword isn’t entirely composed of stars. Binoculars show a steady patch of glowing gas where, right at this moment, a star cluster is being born. It’s called the Orion Nebula. A summertime counterpart is the Lagoon Nebula, in Sagittarius the Archer.
With star factories like the Orion Nebula, we aren’t really seeing the young stars themselves. They are buried deep within the nebula, bathing the gas cloud with ultraviolet radiation and making it glow. In a few tens of thousands of years, stellar winds from these young, energetic stars will blow away their gaseous cocoons to reveal a newly minted star cluster.
Scan along the Milky Way to see still more sights that hint at our home galaxy’s complexity. First, there’s the Milky Way glow itself; just a casual glance through binoculars will reveal that it is still more stars we can’t resolve with our eyes . . . hundreds of thousands of them. Periodically, while scanning, you might sweep past what appears to be blob-like, black voids in the stellar sheen. These are dark, non-glowing pockets of gas and dust that we see silhouetted against the stellar backdrop. This is the stuff of future star and solar systems, just waiting around to coalesce into new suns.
Beyond the Milky Way. Let’s leap out of our galaxy for the final stop in our binocular tour. Throughout fall and winter, she reigns high in the sky during northern hemisphere autumns and winters: Andromeda the Maiden. Centered in the star pattern is an oval patch of light, readily visible to the unaided eye away from urban lights. Binoculars will show it even better.
It’s a whole other galaxy like our own, shining across the vastness of intergalactic space. Light from the Andromeda Galaxy has traveled so far that it’s taken more than 2 million years to reach us. Two smaller companions visible through binoculars on a dark, transparent night are the Andromeda Galaxy’s version of our Milky Way’s Magellanic Clouds. These small, orbiting, irregularly-shaped galaxies that will eventually be torn apart by their parent galaxy’s gravity.
Such sights, from lunar wastelands to the glow of a nearby island universe, are all within reach of a pair of handheld optics, really small telescopes in their own right: your binoculars.
Thanks to John Shibley for his help in writing this article.