What is a Barlow Lens? And Why Every Astronomer Needs One

The Barlow lens is highly rated among astronomers, and it will provide you with a cost-effective way to improve your overall experience by helping you to see both better and further than you ever have before.

We are going to be reviewing this lens in detail, and providing you with all the information about it that you could possibly need. If you are interested in finding out more about the Barlow lens, then you have definitely come to the right place.

What is a Barlow Lens?

The Barlow lenses are amazing optical elements that were first developed by a man named Peter Barlow, who was an English Mathematician and Physicist. This was the man who created and developed the first-ever prototypes for this type of lens, and he did so in 1833.

Over time, these lenses have developed even further, and they are highly popular among the astronomy community.

The modern lenses that are around now have been used in both astronomy and astrophotography, and they work to help increase the magnification of a telescope. 

The Barlow lens works almost in the same way as a classic teleconverter, and it can be used to increase the effective focal length of a photography lens.

Essentially, they are a super cost-effective way for you to increase the magnification of your eyepiece of the lens, and they are great for fulfilling their purpose. 

The Barlow lens actually contains a concave lens that can be placed between the telescope’s objective lens, or the mirror and eyepiece.

They are going to work well to increase the magnification of any eyepiece that is used in combination with them, and you can get up to 2 or 3 times more magnification.

When looking for Barlow lenses you can get those that are either 2x or 3x in strength. The 2x lens will double the magnification that you would usually get, and the 3x lens will triple it. This allows you to have a much better viewing experience, giving you a more improved view.

How Does the Barlow Lens Work?

In technical terms, a Barlow lens is a diverging lens that can be used to increase the effective focal length of the optical system that is being used.

It works to further extend the cone of light that is produced, which allows you to see a larger and clearer image. You can use this lens to increase the focal length of the objective or decrease the focal length of the eyepiece. 

How to Choose a Barlow Lens

When you are choosing the best Barlow lens for you, there are a few things that you should be aware of first. The first of these things is that you will need to choose a Barlow lens that has a barrel size that will be compatible with the eyepiece that you wish to pair it with.

Otherwise, it isn’t going to work, and the last thing you want to do is buy the lens to find that you cannot use it how you wanted to. The size of the barrel is the diameter of the eyepiece tube that will fit into the focuser.

Typically, a standard barrel size is 1 ¼ inch, but there are also some other eyepieces that use a larger 2-inch format. There are other telescopes that will use different formats, so you will need to make sure that you check this before you go ahead and purchase a new Barlow lens. 

Another thing that you will need to be aware of that we have previously touched on is that there are different Barlow lenses that will have different levels of magnification.

The most commonly used magnification is the 2x lens that doubles the magnification of the eyepiece that you are using it with. However, you are not limited to this option as there are other Barlow lenses with 3x magnification or higher.

What you do need to know is that the higher magnifications might not work well with all telescopes, which is why many people will opt for the standard 2x magnification lens. Though, it is up to you to decide which one you think would work best for you.

The Best Barlow Lens - Quick Comparison 

As we have previously mentioned, there are a few different types of Barlow lenses in terms of the magnification that they have to offer.

We are going to provide you with some extra information about the 2x, 3x, and 5x lens options, so you can figure out which one would work the best for you.

Celestron 93230 8 to 24mm 1.25 Zoom Eyepiece & Omni 2X Barlow Lens

In this bundle, you get both the Celestron 93230 and the 2x Barlow lens, getting more for your money. The price of the two of these lenses combined is not too much more than the cost of a Barlow lens alone.

Focusing on the Barlow lens, you would get double the magnification of each eyepiece that you own, and the 2x power of this lens will help you to see further and more clearly.

You can use your original eyepieces to a higher capacity, and it will accept the standard 1.25-inch eyepieces. It even has fully multi-coated optics with blacked edges that allow for excellent light transmission with minimal reflections.

Celestron 93428 X-Cel LX 1.25-Inch 3x Barlow Lens (Black)

This high-quality Barlow lens by Celestron offers triple the magnification of your standard eyepiece, and it will work with any 1.25-inch eyepiece that you have in your collection.

This helps you to get more out of your existing eyepieces without having to spend lots of money. This is the perfect lens for those who have fast and short focal length telescopes.

This lens also has 3 elements apochromatic, fully multi-coated optics that are able to offer brighter and sharper images with excellent color correction.

It even has a rubber grip to help avoid accidental drops, and there is a brass compression ring to hold the eyepiece firmly in place.

Orion 8715 High-Power 1.25-Inch 5x 4-Element Barlow Lens

This Orion Barlow lens is a fully multi-coated lens that will give your 1.25-inch telescope eyepieces an additional boost of five times more magnification. This will provide you with exceptional performance, and you won’t be disappointed with the quality that you receive.

Your eyepieces will work much better than they ever could before, and this lens is the perfect thing for allowing you to observe extremely high-power views of the moon and the planets. This just goes to show how powerful this lens really is. 

It has a 4 element lens design, which helps to preserve the optical quality of your telescope and eyepieces, providing you with much sharper views.

This is the ideal lens for you to use with a solar system imaging camera for high-magnification lunar and planetary astrophotography.

No matter if you have an interest in astronomy, astrophotography, or both, this would make the perfect lens for you. There is also a brass compression ring that keeps eyepieces securely installed without getting scratched.