Many would quickly disregard binoculars and opt for a telescope as if it’s the only astronomical optic worth owning.
If you’re willing to be a little open-minded, you could expand your astronomical collection for better performance.
To keep you from falling into the pitfalls of exclusivity, let’s explore what a binocular can offer the astronomer.
You may be missing out on a whole lot of fun that could get you closer to achieving your goals and enjoyment.
Set your sights over this way as I take you on a mind-opening journey of how binoculars can be an enhancement to your astronomy aspirations and that it’s not an ultimatum situation.
Binoculars for Astronomy
There are binoculars and then there are astronomical binoculars.
They’re basically the same thing, but some binoculars have technical specifications better suited to astronomy.
For the purposes of this article, we will be discussing binoculars with the right specs for stargazing, how they work, why they could be useful to you, and what their weaknesses are.
Binoculars are essentially two, mini telescopes put together to create one optic to provide binocular vision, meaning, you can use two eyes. Instead of calling the individual tubes “telescopes,” most of us refer to them as simply “barrels.”
These barrels house the optics needed to collect light and transmit it towards the eyepiece to the user.
There are two different types of astronomical binoculars you will come across: roof and Porro. They are the names for the prism design within the barrels. You can immediately identify a Porro prism binocular by its off-set objective lenses to the eyepieces – the eyepieces are closer together and the objective lenses are further apart.
Roof prism objective lenses look to be in the same straight line as their corresponding eyepieces. There are benefits and drawbacks to both binocular optical designs.
Each optical design has its own optical path that relies on glass, reflections, and mirror coatings. Sounds similar to a telescope, right? Right!
Like a telescope, you can achieve a magnified view of an astronomical object that the naked eye cannot achieve alone.
- Use both eyes
- Easy to focus
- Easy to use
- Various levels of optical quality
- Many are tripod compatible
- Can be worn around the neck
- Multiple uses
- Can be used for land viewing
- Image orientation is right side up
- Can be weatherproof
- Larger models are expensive
- Larger models must be mounted for stability
- High-quality models are expensive
- Can suffer from optical aberrations
- Binoculars are like telescopes, but with two, mini versions put together
- There are two types of binoculars: Porro and roof prims binoculars.
- They suffer with optical aberrations like telescopes do.
- They are extremely portable and convenient to use.
- They provide high magnification allowing visibility of distant land and astronomical objects.
- They vary in price depending on optical and mechanical quality and additional features.
- Like telescopes, you get what you pay for.
In this context, we will discuss telescopes for the amateur astronomer. While there are very large sizes and telescope variants that are specialized for astronomy in one form or another, I’ll keep it simple. The type of telescopes I’m referring to are available to all in the consumer market, can be bought online, and can cost anywhere between $100 to $5000.
Unlike binoculars that use two barrels to provide binocular vision, a telescope has one tube and provides monocular vision. While there are various types of telescopes and variants within those types, the two most common are refracting and reflecting telescopes.
Refractors use glass lenses and reflectors use mirrors. Some other types of telescopes like catadioptric telescopes use both lenses and mirrors. Each offers a different optical path that provides benefits and drawbacks for astronomical viewing and imaging.
Telescopes are excellent at magnifying a view to acquire visibility on astronomical objects such as the moon, planets, stars, galaxies, nebulae, and more. The dimensions of essential optical components in a telescope largely determines what field of astronomy that telescope excels in.
For example, a telescope with a slow optical speed is excellent for planetary observation. A telescope with wide fields of view can be a great optical tool for getting a closer look at large constellations, galaxies, and more.
- Large apertures
- High magnification
- Interchangeable eyepieces
- Often packaged with mount/tripod included
- Specialized for astronomy use
- Can be compatible with motor and clock drives
- Can be used for astrophotography
- Not weatherproof
- Accessories are expensive but essential
- Multiple accessories may be needed
- Only monocular vision
- Image orientation is upside down
- Must have a mount to move telescope
- Quality telescopes have a moderate starting price point
- There are many types of telescopes that provide different strengths and weaknesses.
- Telescopes can be lightweight and portable.
- Image orientation is not “correct” for land viewing unless the correct accessory is used or modification is made.
- A telescope tube must have a mount to provide movement with a tripod or base to support the platform.
- Telescopes come with larger apertures and provide much higher magnification than a binocular.
- Telescopes can be expensive and you may need to purchase additional, must-have accessories.
- Telescopes cannot be made to be as weatherproof as binoculars.
- Like binoculars, you get what you pay for.
Binoculars VS Telescopes
There is room for both types of optics in the amateur astronomy world. In fact, you may find yourself using both types in any given observation session.
Without bias for either, here is an overview of what you will need when you need it.
One thing that bugs me is the advice to buy binoculars if you can’t afford a telescope. Sure, binoculars may be smaller, but like telescopes, the larger they get, the better quality they have and the more expensive they can be.
In fact, some of the more modest sizes of binoculars with decent optics can cost more, sometimes even three or four times as much, than telescopes in the entry-level market. Hence, a cost comparison of the two simply by “size” is not a fair measurement.
The same way a telescope is valued by its optical components, features, and mount, binoculars are valued by their optical components, features, and accessory compatibility.
But, can binoculars cost as much as high-end telescopes? Absolutely. The additional tech, night vision, thermal vision, and many other features can drive the prices upwards of $10,000. Sure, you don’t need those things for astronomy, but it does give you an idea that optics in general are not cheap.
What does remain consistent across that board that I agree with is, you get what you pay for. . . binoculars, telescopes, or otherwise.
Aperture is the diameter in millimeters of the objective lens in a binocular and the primary light-gathering objective lens or mirror in a telescope. They each serve the same purpose – to collect light to help form a magnified image.
You can identify the aperture in the model name or specs of binoculars when you see two numbers separated by an “X.” For example, 10×42. The second number identifies the aperture. With a telescope, it may be in the model name in millimeters or inches. For example, Celestron NexStar 6SE – the “6” means the NexStar telescope has a 6” aperture.
Binoculars are obviously going to have smaller apertures versus telescopes. Astronomical binoculars should have an aperture between 42 mm to about 100 mm. 42 mm should be the minimum and 100 mm is about the maximum at already expensive price points that can be difficult to use.
50 mm is a good all-purpose size and may be used hand-held if you have a steady hand and are experienced. Otherwise, they should be mounted to a field tripod for steady visibility.
Telescopes come in multiple sizes from as small as 50 mm to as large as 16” and bigger. As such, they can “gather” more light than binoculars and be used to achieve much higher magnification.
Magnification is what allows you to see a distant object as if you were much closer to it. Both optics offer magnification. The magnification factor can be identified in a telescope within its model name or the specs by the two numbers separated by an “X.”
For example, 10×42. Where the second number is the aperture, the first number indicates the magnification setting. Most binoculars will have a fixed magnification, meaning, they cannot “zoom.”
However, some budget binoculars do provide a zoom magnification and very expensive ones offer interchangeable eyepieces. At that point, you may as well go the telescope route.
To determine the magnification on a telescope, you must know the size of the eyepiece. Since a telescope allows use of more than one eyepiece, and you should have multiple eyepiece sizes, you can achieve low, medium, and high magnification.
To calculate the magnification of any given eyepiece with a specific telescope, use this formula:
Telescope focal length divided by eyepiece focal length = magnification/power
For example, 1200 mm / 25 mm = 48x. The 25 mm eyepiece will provide 48x magnification through the 1200 mm focal length telescope.
Binoculars have an advantage because they provide low power (compared to a telescope) which means a much wider field of view – you can fit larger objects within the space of what you see. It may also allow for handheld use, although, 10x can still be difficult to hold steady when you’re looking at the sky for small targets that are harder to identify.
Telescopes with their interchangeable eyepieces and the image stability offered by the mounting platform offers greater advantage. They can offer much higher magnification than a fixed power binocular.
However, very flimsy tripods and low-quality focusers can be unreliable and can produce image shakiness or tremors in the image when you change out an eyepiece or focus the scope. You must wait for it to stabilize itself. Hence, mount quality and accessories are as important as the telescope itself.
Both binoculars and telescopes have a focusing mechanism. On a binocular, the focusing mechanism is usually a center knob or wheel. One of the eyepieces also has an adjustable diopter to focus it for your vision.
Even though many people do not know how to correctly focus their telescope, it’s not difficult if the binocular is made correctly. The focuser provides either single-speed or dual-speed focusing to allow for course or course and fine focusing.
A telescope also has a focuser. There are many types of focusers with the 1.25” rack-and-pinion and 2” Crayford being the most common on amateur scopes. The concept is that when you focus the telescope, you are essentially moving the drawtube of the focuser in and out of the telescope tube.
This causes the eyepiece to be moved up or down to provide the best image possible for your vision. Each type of focuser and their variants provide their own set of benefits and drawbacks.
Once you have the diopter set for your vision, focusing a binocular is very easy and can often be done with one finger. You can make focusing adjustments very quickly.
Telescopes have a steeper learning curve as there are more moving parts and various things that can go wrong depending on the type of focuser such as backlash, slop, image shift, and more.
Size for Portability
Binoculars are obviously smaller in size than telescopes. Like telescopes, the larger the aperture, the bigger and heavier the scope becomes – and price follows suit.
A 10×42 will be much smaller and lighter than a 16X70.
If you’re wearing your binoculars on a harness or neck lanyard, size matters. 42 mm and 50 mm models are weighing in lighter than ever before at anywhere between 21 oz to 35 oz. Yes – ounces.
This is the standard measuring unit for binoculars because they’re so lightweight.
Some advanced models can weigh up to a few pounds or more.
These would be best be mounted to a tripod. Heavy binoculars used in the hand can cause incorrect use of the binoculars, wrist strain, and the inability to stabilize your image. If it’s big, mount it.
Small refractors and tabletop reflectors can be very lightweight weighing in under 10 lbs or even 5 lbs. They’re designed for grab-and-go portability and travel. Larger models weighing in around 20 lbs to 40 lbs are still considered good for travel.
Even though telescopes are significantly heavier than binoculars, you have the advantage of not having to hold the telescope as the mount and tripod or base does it for you. But, you still have to transport, setup, and disassemble it. Binoculars are extremely convenient for travel and instant use.
Telescopes are fragile and reflectors have exposed optics with open tubes. This is not a good mix for wind and rain. Most telescopes have no waterproofing features at all.
Binoculars on the other hand are the complete opposite. They’re very durable and glass components are set in place very well. They can handle reasonable amounts of abuse and still function as if nothing has happened.
Most binoculars are made to be at the very least water-resistant if they’re not fully waterproof. They’re also designed to handle extreme temperature changes unlike a telescope. A lot of the time, when a binocular is made to be waterproof, the optical barrels are also purged with a gas, either Nitrogen or Argon, to provide fog-proof protection.
This isn’t fog that you encounter on a cold morning, it’s referring to internal fogging of the optical chamber due to temperature changes.
Good binoculars will always have optical coatings as a minimum requirement. Therefore, most binoculars will have optical coatings that telescopes may only start seeing applied at their mid-range price points.
Binoculars also have external lens coatings to protect the objective lens from dust, rain, smudges, oil, and other types of debris. These coatings can also repel them.
This one is a no-brainer. Binoculars have prisms built into their optical design. With these prisms, astronomical binoculars are dual-purpose champs. They can be used to stargaze and then switch to land viewing in an instant.
The same pair of binoculars that you use to see the stars can also be used for hunting, spotting groups at the shooting range, surveillance and security, sightseeing, wildlife observation, and much more.
Not all telescopes are suited to terrestrial use, that is, land viewing. Refractors can be used with a prism that works as a diagonal to provide image correct orientation. Because they’re very high-powered optics, you will need to use a long focal length eyepiece to achieve low magnification and get the widest field of view you can achieve.
Binoculars are already made with prisms and they’re designed for close-focus distances with huge fields of view compared to telescopes.
This is what telescopes are made to do – look towards the heavens. They can bring planets right up to your eye, bring galaxies and nebulae into view, can track stars, and more.
Binoculars, for as impressive as they are, will just not see as much as a telescope. If you’re comparing the budget market of telescopes to a binocular, a high-quality binocular would absolutely be superior.
However, these binoculars tend to cost at least twice as much as a budget telescope, so it’s not a fair comparison. You may as well upgrade your telescope for the price that you would spend on a decent pair of binoculars.
What Can You See When Using Binoculars for Astronomy
While telescopes are the clear choice for astronomy for many reasons, you can stargaze without one. They provide an instant and convenient platform for viewing astronomical objects with ease.
It’s faster and easier to setup even with a tripod in use, they provide far more visibility than the naked eye, and they can be used for other purposes.
What space objects can you see with a binocular?
There is a long list of different objects you can try to see. Some of the harder ones to resolve will depend on the specs of the binoculars. Even though many objects may appear as colorless and featureless patches in the sky, some telescopes can’t do any better either.
Instead of leaving the binoculars at home, take it along and use its wide field of view to find targets and get a good look. Then, use your telescope to home in on it. It can be much faster to do this, use your finder scope to nail it down, and then your telescope to observe considerable detail.
You may be happy to know that your stargazing skills you’re learning with your binoculars will be the same skills you need to use a telescope. In fact, star-hopping and using charts and maps may be harder to do with a binocular because telescopes come with motor drives to provide automatic slewing to the object you want to see.
- Moon – Easy to find explore. Phases, eclipses, Terminator line, shadows, seas, mountain ranges, and craters.
- Planets – Mars can be identified. Venus is easily seen and possible to see its phases. Can see Jupiter and its four moons. Saturn is bright and can be seen along with Titan. Discerning its rings is a challenge never mind the division.
- Deep-sky Objects – Deeper objects like galaxies can be seen, but they will appear as “fuzzies.” With applicable galaxies, you will be able to point out nearby stars that help to point towards some of the brightest Messier objects.
Here is a quick-list of objects you can try finding with your stargazing binoculars.
- The Milky Way
- Epsilon Lyrae – The Double Double (double star)
- M13 Hercules Cluster Magnitude 5.9 in Hercules constellation
- M24 Sagittarius Cloud Magnitude 11.5 in Sagittarius constellation
- M31 Andromeda Galaxy Magnitude 4.5 in Andromeda constellation
- M33 Triangulum Galaxy Magnitude 7 in Triangulum constellation
- M39 Open Cluster Magnitude 5.5 in Cygnus constellation
- M42 Orion Nebula Magnitude 5 in Orion constellation
This is by no means the end of it, but it does give you a good idea of the many types of astronomical objects you can have fun trying to spot and explore with binoculars.
Which is Best for You: Binoculars or Telescope?
Both! There is no ultimatum situation here.
They each have their own types of benefits and drawbacks and they can compliment each other when the situation calls for it.
You don’t have to buy new binoculars if you already have one in your possession. Pull it out and see how it performs. If you don’t feel like setting up the telescope, pull out the binoculars. If you want to scan the night sky, do it with your binoculars and then home in on it with your telescope.
Add some flexibility and versatility to your astronomy observations and you may just improve productivity in one night. With either a binocular or telescope in your hand, clear skies to you!