Since the beginning of time, people have been fascinated by the starlit skies and the world that lies beyond the horizon, observing it as best as they could with the naked eye. The enthusiasm is still there, only that now it is much easier to stargaze, thanks to the many optical magnification devices that have become widely available for civilian use. Astronomy binoculars are very popular amongst stargazers; read the following lines to know how to pick the right ones.
They work like an extension of your eyesight, without altering the natural way an image is perceived by your brain, apparently bringing the object closer to you. With a high-quality design, you will be able to see even 50 times more stars than without any optical device; the Moon will be also a lot easier to observe, as will the Sun.
Even though telescopes are more powerful and appreciated by amateur astronomers, they are heavier, bulkier and less versatile, as they cannot be used for many other things except looking at stars and constellations. Astronomy models can be used in many other scenarios, they have a wider field of view (since they have two separate eyepieces), are far more portable and might be cheaper, depending on the brand.
Quality binoculars for stargazing vary in price and design, but they usually have a magnification power between 15 and 25 times and an objective with a diameter of at least 50 millimeters. In order to decide what is best for you, you will need to look at more individual specifications than the common power by objective diameter characteristic.
To begin with, you have to decide how powerful you want the device to be. The first specification that you will read (usually found in the product title, immediately after the producer and model) is the power and objective size, the two numbers being separated by a multiplication sign (for example, 15×70 or 20×100).
The first one or two numerals show how much will the product multiply (in the given examples, 15 or 20 times); the following number indicates objective size (in our example, 70 millimeters or 100 millimeters).
The field of view is next in terms of importance when speaking about stargazing designs. This indicator describes how wide the perspective offered is. It depends on the way the product was designed, and in astronomy, the wider the field of view is, the better.
Having a large perspective allows the user to scan a bigger portion of the sky and also to find patterns and clusters in the multitude of stars shining above us. Usually, it is described as the maximum width perceived at a certain distance, which is given in 1000 feet or 1000 meters. As an example, the next values are what you might commonly see engraved on the body of astronomy binoculars: 357 ft at 1000 yards, 298 feet at 1000 feet. Go for the higher values if you want to have a wide perspective.
Keep in mind that handheld astronomy items are heavier than almost all the other types commonly found on the market. If you are not sure that you will enjoy carrying or holding a big, long and expensive optical device, it might be better not to buy a dedicated product.
Instead, acquiring a powerful hunting or hiking design might be recommended; you can use a pair of excellent Wingspan binoculars for birdwatching and obtain good results when stargazing. However, if you have decided that size is no problem, keep in mind that exit pupils have to be suitable for your eyes, organs that change with age.
The dark-adapted eyes of an adult will open to a pupil with a smaller diameter than you would see in a child. Make sure that their shape is perfectly round – to do this, simply look at the eyepieces, where the exit pupils are mounted.
Another reason why magnification power is important is that not always more is better. This only depends on your preferences and on what you want to explore in the night skies. Some people prefer greater magnification to allow them to explore far away clusters and galaxies, while others desire a wider field of view and an immersive experience that cannot be obtained with an extremely powerful design.
If you want your binoculars to be versatile and fit for other observation situations, such as ship spotting, hunting or hiking, do not go for the large ones as they are less portable and might be too powerful. Many long-range designs feature an individual focusing system (each eyepiece has a diopter adjustment ring, so you have to focus for each eye) that requires no further modifications when the target is changed, but close objects will not be properly focused.
There are astronomy devices that have a central focusing system, which has to be refocused when significantly changing the viewing distances but can acquire close objects.
Check if the desired product has a tripod adapter, especially if they are heavier than 2 or 3 pounds. Even though sometimes a bundle that includes a support and the product can be offered, usually the tripod has to be bought separately. If the design you went for has no adapter, it will be hard to improvise a mechanism to mount it on a steady support, and this will make for less enjoyable use and a decrease in accuracy.
Apart from the aforementioned features, look for all the extras that are offered, such as warranty, waterproofing and how resistant the main body is. Also, try to find a Porro-Prism design, as it is cheaper and better than their equivalent (in terms of price) roof prisms. Solar binoculars are specially coated items that filter the harmful sunlight and allow you to freely observe an eclipse or the dark spots on the surface; unless certified as suitable for this task, do not try to look at the Sun with your binos as this is extremely harmful to your health. Many extras are featured on some products, so keep your eyes open to all the details described by the producer.