Top 5 things to see in the night sky with binoculars — ranked by an expert

Beyond simple naked-eye observing, a pair of the best binoculars are the most accessible way to experience the night sky. They are affordable (although pricier models are available), very easy to use compared to telescopes and they offer a wide range of celestial sights, from our solar system neighbors to distant deep-sky objects. They are great for both beginners, casual observers and even veteran stargazers who want to grab a quick look or spend time sweeping through the Milky Way.

So what are the best night-sky targets for binocular users? There are so many, but we’ve done our best to whittle them down to five of the best that provide a good sense of what can be seen through binoculars. We’ve also accounted for different apertures and magnifications to make sure there’s something for everyone, even kids

The moon

The moon is the ideal starting point for observing with binoculars. As a large target full of intricate features that appear differently depending upon the illumination, the moon rewards return visits, and you’ll never grow bored.

Even low-magnification, smaller-aperture binoculars will show some interesting details. Small 8x40 or 7x50 binoculars are sufficient; you certainly wouldn’t want to go as low as, say, 8x25 because the moon would appear small. While larger magnifications can improve the view, unless you have the binocular mounted on a tripod, the shake from jittery hands can look like moonquakes. If you don’t have a tripod, an alternate solution is to use image-stabilized (IS) binoculars, where the binoculars’ internal electronics are able to remove the jitter from the image, making the view more static.

The illumination on the moon changes across a 29.5-day cycle as the sun rises and sets over the lunar landscape, with phases cycling from new to first quarter, then to full and last quarter and finally back to new again. Often, the best time to observe a particular feature on the moon is when it is dawn or dusk at that location, and the sun angle is low, casting stark shadows. Otherwise, it is difficult to see the relief when the sun is overhead.

Jupiter’s moons

Earth’s moon isn’t the only moon in the solar system that can be seen through binoculars.

A simple pair of 8x40s or 10x50s will be sufficient to watch the four largest moons of Jupiter — Io, Europa, Ganymede and Callisto — circle around the Jovian giant. Unfortunately, these binoculars won’t be enough to show you the belts of Jupiter or its Great Red Spot, but its four large moons, known as the Galilean moons, because they were discovered by Galileo, will appear as pinpricks of light on either side of Jupiter.

It’s fun to follow in Galileo’s footsteps and watch the moons orbiting Jupiter, sometimes disappearing from view as they move behind the giant planet, or pass in front of it. Binoculars will not be powerful enough to show the moons transiting against the face of Jupiter, though — Jupiter is too bright, and the contrast is not great enough. The other 91 moons of Jupiter are far too small and faint to be seen in binoculars.

Mizar and Alcor

In the handle of the pan-shaped Big Dipper (part of Ursa Major) is the pair of stars called Mizar and Alcor. They make a lovely visual double, easily seen with the naked eye, and they really pop when viewed through 10x50 binoculars, with Mizar the brightest at magnitude 2 and Alcor a little fainter at magnitude 4.

Some double stars are just visual doubles, meaning they are many light-years apart and unrelated, but they just happen to be very close to each other on the night sky as seen from our line of sight. Not so with Mizar and Alcor, which are physically bound by gravity as they orbit each other. However, view Mizar and Alcor through binoculars, and you will get a glimpse of the true magnificence of this system. Large binoculars will show that Mizar is also a double star. Resolving Mizar as two stars is probably pushing it in 10x50s, but a pair of 20x80 binoculars will give you a better chance of splitting them, with image-stabilized binoculars, if you have them, giving you the edge.

There’s even more in the Mizar and Alcor system than what binoculars can show. Both stars in the Mizar system are also doubles, as is Alcor, making this a six-star system in total! Sadly, these extra companions are so close together that not even telescopes can split them. But there are plenty of other doubles for you to hunt down with binoculars. The trick is to find double stars that have a wide enough separation to be resolvable by 10x50 binoculars. Try also Epsilon Lyrae and Alpha Librae, also called Zubenelgenubi, meaning ‘southern claw’, as it was once associated with the constellation Scorpius the Scorpion, before being moved into Libra the Scales.

Auriga’s open clusters

Auriga the Charioteer is a constellation famed for two things: its brilliant yellow star Capella (the sixth brightest in the entire night sky), and its array of magnificent open clusters, notably Messier 36, 37 and 38.

Open clusters are young clusters of stars that were born together and are now gradually dispersing, and Auriga’s open clusters are some of the best and brightest of their kind in the night sky.

A pair of 10x50 binoculars can have a field of view between 5 and 7 degrees, depending upon the model. For the larger field, it’s possible to squeeze all three of Auriga’s open clusters into the same view!

To find the clusters, first drop down from Capella to alight on the bright star Elnath, which is actually Beta Taurii in the constellation of Taurus the Bull. You can find Elnath easily with the unaided eye. Switching to binoculars, look about three-quarters of the way along the line between Capella and Elnath. You should see six fainter stars of magnitude 6 forming a curve. Follow that curve west, and you’ll come across two other magnitude 6 stars close to M38, which appear as a hazy patch whose diffuse light is made from a multitude of faint stars. This is the case for all three clusters. Most of M38’s stars are not resolvable in binoculars, but some certainly are in 10x50s, and switching to larger aperture binoculars or an image-stabilized model will help to reveal more.

Just 2.5 degrees to the south-east is the next cluster, M36, which overall is brighter than M38. Through 10x50s look for eight or ten stars; again, large binoculars will reveal more.

Finally, M37 is located a little further away. The constellation of Auriga has an obvious five-sided shape marked by its main stars and Elnath. Draw an imaginary line between Elnath and Auriga’s bright star at its lower left, magnitude 2.6 Theta Aurigae. Messier 37 is found about halfway along and just outside of this line. Another hazy patch, it is the densest of the three clusters, but most of its individual stars are fainter than in M36 and M38, so M37 will need larger binoculars, say 25x100, to get the best out of it.

After spending time looking at the three clusters, sweep your binoculars along the splendor of the winter Milky Way, in which Auriga sits. Through binoculars, the vast star fields of the Milky Way are spellbinding.

The Andromeda Galaxy M31

The Andromeda Galaxy (Messier 31) is the closest large spiral galaxy to our Milky Way galaxy, located 2.5 million light-years away. That means it is large and relatively bright in our night sky, making it a great target for binocular users. If you are observing from a dark site away from city lights, you will probably be able to see it with the naked eye.

If you can’t or are having trouble knowing where to look:

• Use the stars of the nearby constellation Cassiopeia to find it. Cassiopeia has the shape of the letter ‘W’. Use the bottom star on the right of the W — the brightest star in Cassiopeia, Alpha Cassiopeiae or Schedar — to...

• Point down towards Andromeda and its bright star Beta Andromedae, or Mirach.

• Now using 10x50 binoculars, move north-west until Mirach is at the bottom-left of your field of view and the star Mu Andromedae is at the top-right.

• Then move your binoculars the same distance in the same direction again, and you should find the Andromeda Galaxy.

While you won’t be able to resolve its spiral arms, you will see a smudge of light that is its disk, and a brighter core. Also look out for its two companion galaxies, M32 beneath it and M110 to the top-right. Both appear as fuzzy stars and, depending on how dark your observing site is, you may need to use averted vision to see them (looking at them out of the corner of your eye). Larger binoculars, say 25x100, will show M31 and its companions much more easily, though you’ll need a tripod to take their weight.

Gemma currently works for the European Space Agency on content, communications and outreach, and was formerly the content director of Space.com, Live Science, science and space magazines How It Works and All About Space, history magazines All About History and History of War as well as Science, Technology, Engineering, Arts and Mathematics (STEAM) kids education brand Future Genius. She is the author of several books including "Quantum Physics in Minutes", "Haynes Owners’ Workshop Manual to the Large Hadron Collider" and "Haynes Owners’ Workshop Manual to the Milky Way". She holds a degree in physical sciences, a Master’s in astrophysics and a PhD in computational astrophysics. She was elected as a fellow of the Royal Astronomical Society in 2011. Previously, she worked for Nature's journal, Scientific Reports, and created scientific industry reports for the Institute of Physics and the British Antarctic Survey. She has covered stories and features for publications such as Physics World, Astronomy Now and Astrobiology Magazine.