Telescope 10mm vs 20mm- Choose the Right One!

Telescope 10mm vs 20mm- Choose the Right One!

Who doesn’t want to know what lies beyond the visible sky? We all do it, right? And the telescope is the wizard which takes us to explore the sky on it’s magical ride. But choosing the right telescope for the right purpose.

So, when it comes to the telescope 10mm vs 20mm, which do you prefer?

The 10mm eyepiece provides 100x magnification and the 20mm provides 50x magnification. Though the 20mm lens also has a larger field of view than the 10mm. You can use the 20mm eyepiece for Deep Sky objects such as clusters, and the 10mm eyepiece for the moon and planets.

Do you find these facts useful? Great! Then you are exactly in the right place. Let’s dive into our next segment where we have discussed both sides of the coin, that will help you to choose your telescope easily.

Hop on-

Telescope 10mm vs 20mm: Differentiate all the Parameters

Let’s go through some of their key attributes to help you decide which one to pick from the table:

Features10mm 20mm
View FieldWider with angle 41°Less wide with angle of 56°
ObservationUsed for close objectsUsed for distant objects

This was it for a quick comparison. We have a detailed comparison in the next segment.

Detailed Comparison of Telescope 10mm vs 20mm

We have seen the compact overview of these articles. Now let’s dig deep into the details-


Both 10mm and 20mm telescopes are not very different in the comparison of pricing. Since a 10mm telescope has less magnification power so it costs a lesser price as well. And on the other hand, 20mm telescopes are a little expensive. 

Usually, 10mm telescopes range between 3600 to 3900 US Dollars and 20mm telescopes range between 4900 to 5000 US dollars.

Winner: 10mm telescopes


Since eyepiece eyeglasses suitability is determined by barrel size, it’s not like all telescopes have a relatively similar focal length or magnification. The barrel size of the eyepiece will be marked into the housing next to the focal length and perhaps displayed in a different handbook.

When selecting an eyepiece, eyeglass wearers should consider the focal length split by the barrel size of the eyepiece. It is exactly like how we compare 10X50 and 20X50 binoculars.

The eyepiece and magnification are also determined by the lens & magnifying dimensions. 20mm telescopes have a bigger diameter than 10mm eyepieces, so objects appear larger when viewed through them.

Eyepiece focal length is also measured in mm, and the longer the focal length, the larger the magnification you can get from your telescope.

10mm eyepieces produce a medium-low magnification, whereas 20mm telescopes magnify 50% stronger. 

It’s because eyepiece diameter, as well as field of view (FOV), go hand-in-hand: larger diameter eyepieces provide such a wider FOV, which means you can see more detail once looking through higher magnification eyepieces.

Winner: 20mm telescopes

Here’s our recommendation for some fine quality 20 mm eyepieces out there.

View Field

When looking at star clusters or galaxy groups with two to three bright stars close together with telescopes with focal lengths less than 20 mm, there are often gaps between the eyepiece’s FOV and individual stars in these objects. 

This is due to the fact that you can’t fit all of the stars in one eyepiece frame because they’re too far apart. The 20mm eyepiece, in particular, has a FOV of 56°, whereas the 10mm eyepiece has a wider 41° FOV. 

Winner: 10mm telescopes

Observing Objects

10mm telescopes are usually used for close objects, on the other hand, 20mm telescopes are used to observe distant objects. So, profound Astro objects including clusters, nebulae, and galaxies can be seen through the 20mm eyepiece, while the moon and other planetary systems can be seen through the 10mm eyepiece.

But one disadvantage of using higher magnification telescopes like a 20mm telescope is that you can’t see that much at once. It’s because the objects look smaller through them than through low magnification eyepieces, however, this is a personal preference. 

Some people prefer to get as far as possible at once, while others prefer to focus on eyepiece sharpness rather than a small portion of the object.

Winner: 10mm telescopes


When looking for eyeglass-friendly top-notch eyepieces, look for ones with a minimum of 20mm focal length.

Anything less than 20mm will be too near to your head. And may not give you sufficient room to observe the perceptible field of view via the telescope optic disc without having to move your head posture.

When selecting eyepieces consider selecting 20mm of focal length or more than that if you want to move your head while enjoying the stargazing. This will ensure that you have sufficient area to gaze via your eyepiece without having to adjust your eyeglasses as well as head position.

Winner: 20mm telescopes

These were the brief comparison of these two telescopes. However many people prefer to make customized telescopes. For example, you can make a solar telescope exactly how you like it. So you can combine these lenses if you want.

Final Verdict

Now, you know the pricing cannot be an issue between these two telescopes. Both are budget-friendly and come at a similar range of price. So I recommend comparing on the basis of the rest of the parameters.

I prefer 10 mm telescopes for the moon and planets. It provides a wider view field and also it shows a larger area all at once, which 20mm telescopes don’t. Though it is true that 20mm telescopes have more magnification powers, so you can easily get a view of distant objects like nebulae and other galaxies. 

Honestly though, I take more interest in the moon and planetary stars. However, the view is better as it is wider in 10mm telescopes. 

On the other hand, 20mm telescopes are more eye-friendly and users can easily move their head postured backward and forward. So, it is convenient for those who like to work with movements and change their positions.


Question: How much magnification does a telescope eyepiece have?

This is a number that is usually printed or emblazoned near the eyepiece focal line and ranges from 400- to 3000-mm, relying on the aperture as well as type of telescope. Telescopes have focal lengths as well, such as 25- or 10-mm, and so their own magnification.

How much magnification does a 25mm eyepiece provide?

Telescopes have focal lengths as well, such as 25- or 10-mm, and hence their own magnification. Simply split the focal length of the field of view by the focal length of the eyepiece to calculate magnification. A scope with a focal length of 2000 mm and an eyepiece with a diameter of 25 mm will thus provide 2000/25 = 80 power (or 80x).

How large of an eyepiece can you use with your telescope?

You can easily calculate the longest-focal-length eyepiece you could use on your telescope by multiplying the focal proportion (the focal length of the scope split by its aperture) by 7.

What Effect May Eyepiece Focal Length Have on Glasses Wearers?

A lesser eyepiece focal length indicates that the eyepiece is best suited for use with spectacles than a greater eyepiece focal length. A greater Focal Length Eyepiece, on the other hand, provides more expansive views of objects. 

Wrapping Up

I hope you are no longer baffled by the telescope 10mm vs 20mm debate. Each individual’s requirements are unique.

After comprehensively comparing each of these filters, select the one that relates to your priority list most. We’d be delighted to assist you in this matter. 

Continue to spread the word! Till our next visit, enjoy your stargazing!

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