The ability to quickly and accurately focus on an object can be the difference between seeing that rare bird and hearing about it. Can you maintain accurate focus or will you accidentally offset the diopter, giving you a blurry image? For the ease of adjustment category, we looked at the following items: how quickly one can focus from one spectrum to the other, how easy it is to focus on an object to get the most detail, and how easy it was to adjust the diopter and did the diopter lock. We also evaluated the interpupillary distance adjustment. Except for the locking diopter, the criteria was a subjective and based solely on several testers' opinions.
Because the human pupil is about the same size as the binoculars' exit pupil, the emergent light at the eyepiece then fills the eye's pupil, meaning no loss of brightness in low light conditions due to using these binoculars (assuming perfect transmission). Thus the result is that you will perceive the image as being as bright as if you were to see it with the naked eyes.

So as you can see, for astronomy you are looking for an exit pupil of 5 or more, however with higher magnifications this is not always possible as the objective lenses would have to be massive. So whilst many giant binoculars have slightly smaller exit pupils than the ideal, they are still large enough to provide you with a bright enough image - however this is where the amount of transmittance becomes really important (see below).
Inside, things are more or less what you’d expect from a pair of binoculars like these. The prism is a Hi-index BAK4 prism, which has been proven to give you a sharp and bright image, with plenty of contrast. When you’re looking at an object, you can be sure that you see every little detail of it. The 22 mm lens design won’t cause any eye fatigue, or dizziness, and your view will be a combination of HD and wide angle. The 50 mm objective lens, on the other hand, is large enough to ensure that even in low light conditions, such as at dawn, or at dusk, or even at night, you will receive as much light as possible inside, making the image bright.
Everyone talks about magnifications and there is no doubt that high magnifications yield beautiful views of the Moon, planets and fine detail in some deep sky objects. However, many objects in the sky are too large to fit into the field of view of a high power eyepiece. These objects demand a wide field of view to appreciate their beauty and delicate form.

We spent 45 hours on research, videography, and editing, to review the top choices for this wiki. Ever since ancient times, mankind has gazed up at the skies in wonder. Some of our most profound discoveries came from people who had little more than their eyes and their wits to consider the cosmos. But these astronomy binoculars give modern-day stargazers capabilities the geniuses of old could only have dreamt of, bringing the mysteries of space closer than ever before. When users buy our independently chosen editorial picks, we may earn commissions to support our work. Skip to the best astronomy binocular on Amazon.
These binoculars are no joke! Weighing in just under nine pounds, the Celestron SkyMaster ASTRO Binoculars are ideal for beginner or expert astronomers and stargazers, alike. They feature a humongous aperture, a pair of giant 100mm diameter lenses, and quick 25x magnification to capture images in near-pitch black conditions, while delivering spectacular views and details that might make you think you work at NASA. Although they come with a deluxe padded carrying case, you might also consider getting a tripod considering their heft.
Recommendation: balance and handling is a very personal thing, but you should be able to get some idea of what the binoculars on your shortlist are like by reading reviews online from people who’ve spent time with the binoculars on your short-list. Try searching birding and wildlife forums (like Bird Forum) for recommendations by owners — and try and get to use as many different types of binocular as you can to see how different models and different styles feel to you (see point 10 on Try Before you Buy).

Another way to express the viewing angle is the Apparent Angle of View (AAoV). This is roughly calculated by taking the AoV and multiplying it by the magnification. So if that 10x42 binocular from the earlier example has a 6.3-degree AoV, its apparent angle of view is 63 degrees. The AAoV is the angle of the magnified field when you look through binoculars; so the larger the apparent field of view is, the wider the field of view you can see even at high magnifications. Generally speaking, an AAoV of more than 60 degrees is considered wide-angle. Nikon engineers developed their own mathematical formula to determine AAoV (see below) more accurately and precisely, which lowers the angle on average, but most of the optics industry continues to use the first formula for consistency and simplicity.

Binoculars are not required for birding, of course. Audubon’s Eric Lind recommends going out with a group of birders and trying their binoculars before you make a purchasing decision. The social aspects of birding, the sharing a sense of wonder and discovery, and the life-long learning experience is what makes birding so popular. There is no better way to cultivate that aspect of birding than through sharing the view of a bird through a friend’s binoculars or by handing your favorite pair to a family member to let them share in the experience.
The low price does necessitate some drawbacks. The rubber coating of the Nature DX 8x42 feels of a lower quality than higher priced models and the hinges likewise feel slightly less sturdy. The glass is also lower quality, so lowlight situations will yield slightly dim images. However, the large 42mm objective lenses do help in these situations, making these binoculars perform a bit better in low light than the compact models often found in this price range. Overall these complaints are minor, and we would wholeheartedly recommend these bins to anyone looking for their first pair on a budget.
The next most important specification on binoculars is the field of view. It will be represented in one of two ways: feet at a distance of 1,000 yards, or degrees. The higher the number of feet at 1,000 yards, the larger the field of view. When expressed in degrees, the higher the number of degrees, the larger the field of view. As the magnification power of binoculars increases, the field of view generally decreases. If you prefer the immersive space walking experience, choose a model with a wider field of view. This will make it easier to pan across the sky and find different celestial objects to view. If you prefer to see those celestial objects in the maximum amount of detail, opt for a pair with a narrower field of view and stronger magnification capabilities.
Close focusing is key when trying to see detail on things like butterflies, wildflowers, and the like. Our pick gets as near as 6.5 feet, and though a few binoculars focused closer than that, several contenders didn’t get anywhere near getting near. The Nikon Prostaff 5, for example, couldn’t bring objects any closer than 16 feet into focus. We liked the Prostaff 5 as a budget pick, but we warn that they’re not for looking at butterflies or anything that requires getting ultra-close for detail.
Bill Stewart says that he has seen many beginning birders make the mistake of buying binoculars based on a brand or recommendation and then finding themselves disappointed with the feel or view they experience in the field. He also has seen birders “buy down instead of up” to save some money initially. They often end up spending more the second time around when they feel that they need to upgrade to a better pair, he says.
A super-rugged set of binoculars, these 15x70s are optically outstanding. Looking through the Ultras' exquisitely multicoated glass, you may find yourself falling in love with the sky all over again. Oberwerk's method of suspending its BAK4 glass Porro prisms offers greater shock-resistance than most competitors' designs do. While costlier than some comparable binoculars, the Ultras deliver superior value. Our only complaint is their mass: At 5.5 lbs. (2.5 kg), these guys are heavy!  You can hand-hold them for a short while, if you're lying down. But it is best to place them on a tripod, or on a counterweighted arm, unless you like shaky squiggles where your point-source stars are supposed to be. Like with most truly big binoculars, the eyepieces focus independently; there's no center focus wheel. These "binos" are for true astronomers.
Swarovski’s EL 10×42 is a fantastic  pair of rangefinder binoculars. The specifications only confirm that, but you’re more than likely more interested in how they stack up, rather than numbers. They look very good, with a dark green armor that’s actually very pleasant to hold with it’s texture and warmth. The cutouts on the back make them even more comfortable to hold. It has a Hawk badge embedded, which gives it a very classy look, and Swarovski claim that it’s also hypoallergenic. The bridge area has the same armoring, and all together, this is a very elegant pair of binoculars with rangefinders. The body has an open-bridge design, and it’s a bit longer than the Zeiss Victory we’ll discuss a bit later on. The weight is around 840 grams without the strap or caps, which is a pretty respectable weight for a premium pair of binoculars. The body makes use of magnesium alloys, and it is sealed against water up to 4 meters.

One of the easiest ways to take a spacewalk without ever leaving Earth is to scan the night sky with binoculars from the comfort of a reclining lounge chair on a clear, dark night. But for the best experience, you better make sure those binoculars are actually designed for astronomy. To see our picks for the best binoculars of various sizes and specialties, read our Best Astronomy Binoculars: Editors' Choice wrap-up. If you'd like help picking for yourself, there are a few things you need to know.