Best Astronomy Binoculars 2020

When it comes to stargazing and exploring the cosmos through a lens most people would probably call to mind the image of an astronomer’s telescope. These have their obvious benefits and we’ve outlined some of them in our post about the best telescopes for kids and starters. However, astronomy binoculars offer an affordable alternative that are not only cheaper but have the added benefit of being easily transportable and useful for day time use in all kinds of circumstances.

Some astronomers use astronomy binoculars in conjunction with their telescopes.  They scan the night sky with the binoculars to find an object then use the telescope to examine it in more detail.  These same binoculars might also be used at sporting events, concerts, or bird watching, but they need to be lightweight so that they are not cumbersome to use when swapping between telescope and binoculars.

All the below binoculars are best sellers on Amazon each with great reviews. Celestron are a brand leader in both telescopes and binoculars, as well as other optical instruments.

SaleBestseller No. 1
Celestron 71018 SkyMaster 20 x 80 Binocular
  • 20x magnification porro prism binocular
  • Giant 80 mm objective lens offers maximum image brightness in low-light and long-range conditions
  • Ultra sharp focus across the field of view
  • Large center focus knob for easy focusing
  • Multi-Coated optics for sharp, clear views
SaleBestseller No. 2
Celestron 71009 SkyMaster 15 x 70 Binocular
  • 15x magnification porro prism binocular with ultra sharp focus across the field of view
  • Large 70mm objective lens offers maximum image brightness in low-light and long-range conditions
  • Ultra sharp focus across the field of view. Twilight Factor: 32.4
  • Multi-Coated optics for sharp, clear terrestrial and astronomical views
  • Protective rubber easy-grip covering and included carrying case for safe transportation
Bestseller No. 3
10x50 Binoculars for Adults - High Power, Professional HD Binoculars. Very Powerful for Long Range Views and Big Objectives for Clarity. Great for Astronomy, Hunting & Outdoor. Includes Case and Strap
  • EUROPEAN COMPANY WITH 96% SATISFIED CUSTOMER RATING – 2 YEARS OF WARRANTY - Our Slokey 10x50 Binoculars have a 2-year warranty that ensures you exceptional quality and durability giving you years of enjoyment. Tested by thousands of satisfied customers, YOU are guaranteed to love them… BUY TODAY AND SAVE!
  • HIGH POWER, LONG RANGE BINOCULARS – YOUR BEST CHOICE FOR ASTRONOMY AND HUNTING - Get the ideal power to see in great detail… 10x magnification binoculars. YOU will get large objectives to achieve MAXIMUM light transmission… making the Slokey 10x50 YOUR - BEST - CHOICE for hunting and astronomy because YOU can use them in LOW LIGHT conditions. They will also be great for many more outdoor activities such as nature watching and camping… Add them to your cart and enjoy their wonderful views!
  • CLEAR, SHARP AND BRIGHT VIEWS – YOU WILL BE AMAZED BY THEIR LUMINOSITY - Get the Slokey 10x50 binoculars equipped with optical lenses Fully Multi Coated (FMC) and BK7 prisms to achieve views with an amazing brightness… PLUS you avoid any distortion on the views thanks to their lens treatment so that YOUR views are the most faithful to the real color of the image… Get the binoculars YOU deserve today… 9 out of 10 people who tried our binoculars say they would recommend them to their friends.
  • SOLID AND ELEGANT STRUCTURE WITH A VERY COMFORTABLE GRIP - Aluminum body with durable rubber coating to ensure you a GREATER DURABILITY that will resist the most difficult weather conditions such as rain, fog and dust... YOU will also get a water-resistant non-slip surface PLUS a comfortable and steady grip for YOU to enjoy them to the fullest. * IMPORTANT: They weight 765 grams... If you prefer lighter binoculars, we recommend you our Slokey 8x32 or 10x42.
  • NEED ADVICE CHOOSING BINOCULARS? - Choosing binoculars can be difficult... We make it easy for you. The Slokey 10x50 are ideal for low light conditions activities such as astronomy and hunting (they can also be used during the day). The Slokey 10x42, being lighter, are more versatile and can be used for practically everything: hunting, camping, hiking... The Slokey 8x32 have less power but a wider field of view, the best for birdwatching, PLUS they are even lighter and 100% waterproof…

Astronomy Binoculars Buyer’s Guide

It’s worth paying a little more for your astronomy binoculars because of the differences between the cheaper models that deliver views with blurry edges and the clearer, more accurate binoculars that minimise this image distortion.  The better binoculars are those with lenses created with extra low dispersion (ED) glass. This type of glass is used in all kinds of optical instruments due to its ability to produce clearer images.  

Prism Types

As well as the glass there is the prism type to consider.  The consensus among stargazers is to choose astronomy binoculars containing a porros prism type as this kind of prism delivers more light from fainter celestial objects.  For all other daylight use the roofer type prism is the norm as it is smaller and therefore allows for smaller and lighter binoculars.

Build Quality

Another factor to think about is the built quality of the binoculars. They are likely to be exposed to cold, moist air during the winter months.  There is also a risk that they may be dropped or knocked during fieldwork, and we must also consider that since they are handheld devices pressed against the eyes, the look and feel of the materials used is a factor.


Magnification is another variable, but generally speaking the greater the magnification, the heavier the binoculars, so you’ll need to find a happy medium.  Heavy binoculars can soon feel like a burden for tired arms but people vary so the right pair for you may be heavier or lighter than the pair suitable for anyone else.

The higher the magnification the more apparent is the shakiness you see when viewing objects.  If your binoculars are too heavy for you and the magnification is on the high side then your view will be spoiled by the shaking.  You could mount them on a tripod to overcome this, or simply buy a lighter pair with lower magnification.

Magnification is denoted by the first of the two numbers you’ll see in all the product descriptions.  Thus 8 x 42 binoculars will magnify images to eight times what you can see with the naked eye. A magnification of up to 10 is most suitable for astronomy.

Best Astronomy Binoculars

Lens Diameter

However, the second number denotes the diameter of the binocular’s lenses, and this is actually more important than the magnification.  Lenses collect light from objects so the larger the lens, the more light they collect. The human eye’s lens diameter is about 6mm, so you can imagine how much more light a lens that 42mm can collect.

Thus 8 x 42 or 10 x 50 are suitable for low light conditions and sky watching.  They are also useful for sailing when you might be looking into the distance under cloudy skies, or at dawn and dusk.

 7 x 35 and 10 x 32 are best for daylight outdoor use (bird watching, camping etc), and 8 x 25 and 10 x 25 ten to be the lightweight set for general use at track and sporting events.

Field of View

Another point worth mentioning is the trade-off between magnification and field of view i.e. the total amount of sky you can see through the lenses.  Higher magnification binoculars obviously help you to see more detail but they show a smaller field of view. This means it’s less easy to find objects in the night sky because you’re looking at less of it and you won’t see as many reference points that help locate an object. 

It’s a bit like being too close to a location on Google Maps.  You sometimes have to zoom out to see where it is in relation to more familiar landmarks.

Exit Pupil

The exit pupil is another measurement you’ll see mentioned with regard to binocular specifications   This value is the result of dividing the lens diameter by the magnification, so a 7 x 35 pair will have an exit pupil measurement of 5mm (35 divided by 7).

Ideally this figure should be higher than 5mm.  In dim light the human eye’s pupil can widen to 7mm, so if your binoculars can improve on that, so much the better.  A 7 x 50 pair for example would give you a value of 7.14mm.

Relative brightness is a measurement related to exit pupil and is calculated by squaring the exit pupil value e.g. (7.14 x 7.14) equals 50.97.  That is more than twice the relative brightness of a pair of binoculars with an exit pupil of 5mm – (5 x 5) equals 25.

Eye Relief

Binocular eye relief is a measurement of the distance from the eyepieces to the eyes while the whole field of view is in view.  The best option is a longer eye relief.

Field of view is usually denoted in feet and as previously mentioned this decreases with increased magnification.  

Most binoculars have a central focus wheel but some may have what’s called a diopter adjustment ring on one of the barrels.  This is designed to help those who need to compensate for differences between their two eyes.


Before you buy your first or next pair of astronomy binoculars, think about how you’re likely to use them.  If you plan to have fixed in one place, perhaps even on their own tripod, then you could opt for a heavier pair.  If on the other hand you will also use them on field trips, camping, sailing, or going to any sporting events, go for the lighter pair.  Your neck and your arms will thank you for it.

Last update on 2021-11-27 / Affiliate links / Images from Amazon Product Advertising API

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