Binoculars vs Telescope – A to Z Guide

Taking the first steps in astronomy is never easy. That’s why we are going to try to make it easier for you and to clarify some concepts from the beginning. Precisely one of the most common questions when starting in astronomy is: Is it better to start with a telescope or binoculars? In this article we will try to help you decide between a telescope and astronomical binoculars.


Telescope or astronomy binoculars. Where to start?

When the astronomy bug wakes up in us we get nervous, we want to have everything clear and have it now. We start looking at telescopes and get lost among the many models, brands and designs. If you have already decided on a telescope, the best thing is to learn what types of telescopes there are and which is the best telescope to start with.


We recommend not to start directly with a telescope. If you are not sure if you are really going to get hooked on astronomy and you don’t want to invest that much money, why don’t you start with astronomical binoculars?


Telescopes are not the only way to observe the sky. Going straight for a telescope, without having too much experience, can be a mistake and you will most likely end up getting dust in your storage room.


Binoculars in astronomy

Many people are surprised at how much can be seen in the sky even with the naked eye. From a dark sky, and if we know where to look, we can see not only the planets, but also objects like the Pleiades cluster, the Andromeda Galaxy, the Perseus Double Cluster. And if we can observe all this with the naked eye, with a more powerful medium such as binoculars, we will be able to observe even more.


The binoculars have the advantage of being a much simpler, more affordable and more manageable device. Therefore, they are a good option to discover if we are really hooked on astronomy. And we’ll have time to keep moving forward and make the leap to the telescope.


Tips for finding good astronomical binoculars


Let’s look at the differences between binoculars and telescopes, what you can observe with each and what the advantages and disadvantages are. Let’s get started.


Weight and ease of use of the binoculars

One of the first things to consider when buying – or not buying – a telescope is what use we are going to give it. It will be useless to buy a 30kg telescope if we have a herniated disc and we are not going to be able to mount it or a five-foot-one if it is not going to fit in our car. It will seem absurd but worse things have been seen. Therefore, the weight is a fact that we must take into account. The binoculars can be taken everywhere in a much more comfortable way than a telescope, which will allow us to use it in a greater number of occasions. In addition, they are much more intuitive to use than a telescope.


On the other hand, who doesn’t have a pair of binoculars at home? Any binocular can be used to start observing the sky, although at the end of this article we will see what features we should take into account when choosing binoculars for astronomy.


Prices and models of astronomical binoculars

It is also clear that the price of a pair of binoculars can be much lower than that of a telescope. There are decent binoculars at very affordable prices, whereas to find a telescope with a minimum of quality we will have to spend much more. Here you can find a lot of binoculars.


Difference between binoculars and telescopes

Yes, the binoculars are very good. But what’s the difference between observing and a telescope? The differences when observing are many but we can summarize them in these concepts: field, magnification and binocular vision.


Telescope vs. binoculars: binocular vision

In general, binocular vision is more comfortable, since when looking with both eyes at the same time the brain works as usual, receiving the same information for each eye instead of just one, as is the case with telescopes. This makes our eyes more relaxed and allows us to observe more calmly and perceive more details. However, many people are unable to put the two images together and, no matter how hard they try, they still see two separate images. Before you buy binoculars, make sure that this is not the case with you.


Binoculars in astronomy. Features.


When choosing a pair of binoculars, there are several things to look out for:


Magnification and aperture of the binoculars

All binoculars are referred to by two numbers: 10×50, 7×50, 12×60, 8×40, etc. The first number indicates the magnification and the second number the diameter of the lens in millimetres.


The larger the diameter, the more light it captures and therefore the weaker the object. But we also have to take into account that the larger the diameter, the greater its weight and the more it will cost us not to shake the pulse.


Similarly, a higher number of magnifications will not always be better. If we look at a higher magnification, our pulse will affect the image more and it will be more difficult for us not to tremble. We must find a balance between the two. That is why, unless we use a tripod, it is not advisable to go beyond 15 magnification or 60mm.


Exit pupil

It is the diameter in millimeters of the cone of light that reaches our eyes. And it is obtained by dividing the diameter of the lens by the number of magnifications (in about 10×50. 50/10=5mm exit pupil).


This parameter is much more important than we think and we must take into account the conditions in which we are going to observe. The human pupil under optimal conditions (total darkness) dilates to a maximum of 7mm. Moreover, this capacity also decreases with age, and adults do not usually go beyond 5 or 6mm.


So, if we have 7×50 binoculars with a 7mm exit pupil and we are observing from a semi-urban nucleus (our pupils will not exceed 5mm in diameter), much of the light captured by the binoculars will not enter our eye and we will be losing it. Therefore, the most suitable binoculars for astronomy are those that give us an exit pupil of about 5mm, such as the 8×40 10×50, 12×60, 15×75, etc.


Weight of binoculars

It seems that we have already reduced the types of binoculars to a few but we still have to find out if we are interested in 8×40 or 15×75.


Clearly, 15×75 binoculars will be able to capture much more light than 8×40 binoculars and we’ll see more detail with them. This is true, but holding 15×75 can be really complicated, so we’ll come back to the weight issue.


About 10×50 is ideal for freehand use in normal conditions. They weigh no more than 1kg, are easy to use and have a diameter of 50mm -not insignificant compared to our “small” pupils of 5 or 7mm-. As a rule, a tripod is suitable for binoculars from 10×50 upwards. Therefore, if we are going to use about 15×75 we will need, almost obligatorily, a tripod. This means that we lose two of the great advantages of binoculars, their simplicity and their ease of use.


Final reflection. Telescope or binoculars to start with?


With this article we do not intend to convince anyone to buy binoculars or that this is the best option for all cases. Each person should analyze his or her situation and think about what is best in each case. I myself started directly with a telescope and it was a great experience.


What we do want to make clear is that starting with binoculars is perhaps the best way to ensure that this recent interest in astronomy is not a passing fancy and that we really like and enjoy it. If we discover that this interest has really become a hobby, it is when we should consider buying a telescope.