apochromatic vs achromatic

Apochromatic Vs Achromatic: Which Telescope Is the Best?


Choosing the right piece might be hard if you’re new to telescope hunting because telescopes come in many variations. You might find yourself tangled between options like apochromatic or achromatic telescopes.

So, which one is better apochromatic vs. achromatic?

For starters, apochromatic telescopes have better optical quality. Because they offer versatile optical options. Achromatic, on the other hand, has fewer optical elements. Apochromatic also has higher color accuracy and provides stellar photos. But they are heavier and much more expensive than achromatic telescopes.

That was only a preview of the whole discussion. We’ve presented you with a detailed comparison between both telescopes. Read along to get a clear idea about them.

So, let’s begin!

Basic Differences In Apochromatic Vs. Achromatic Telescopes

Before we move on to a detailed discussion, let’s gather some surface ideas. This table will help you pick your thoughts-

Aspects Apochromatic Achromatic
Optical Quality More enhanced optical elements less Less optical elements
Wavelength Corrects three wavelengths Corrects two wavelengths
Weight Heavier  Lighter
Color Accuracy Better color accuracy level Good color accuracy level 
Expense Expensive Cheaper

That was the sneak peek of our discussion. Let’s move on to a detailed conversation about them.

Difference Between Apochromatic Vs. Achromatic Telescopes

Understanding telescopes takes work. You’d need to know the details to determine which is better. The difference in the quality and price is initially big between apochromatic and achromatic. Now, let’s begin our detailed discussion about the differences between these two telescopes.

Optical Quality

An apochromatic telescope consists of a series of three lenses. It’s also known as an apochromatic triplet. These lenses are made from different types of glasses. So, it provides a better correction of aberration. 

It also reduces the dissemination between monochromatic and achromatic lenses. It has more varieties of optical qualities, thanks to the advanced manufacturing processes. This is similar to how Cassegrain and Newtonian telescopes work.

Achromatic telescopes use a series of two lenses. One of them is called one convex. And the other one is a concave lens. 

These lenses are also made from different types of glasses. Concave lenses are made from one kind of crown grass. It has fewer optical qualities than apochromatic lenses. 

In terms of optical quality, apochromatic telescopes win.


Apochromatic lens corrects for three wavelengths. They are the three main colors blue, red, and green. These corrections affect the image quality. 

The lens reduces chromatic aberration for two wavelengths and spherical aberration for one wavelength. The wavelengths in the apochromatic lens have a focus on a singular point.

An achromatic lens, on the other hand, corrects for two wavelengths. They are blue and red. Just like apochromatic wavelengths, these wavelengths have a single focus point. The lens reduces chromatic aberration by using different types of glasses for lenses. 


Apochromatic telescopes are much heavier and bigger than achromatic ones. Since these lenses have larger focal lengths, they are bound to be big. 

As a result, these telescopes become much heavier. Hence, moving, balancing, or maneuvering them takes work. 

In reverse, achromatic telescopes are lighter than apochromatic telescopes. It has fewer optical options. 

Also, the focal point isn’t as lengthy as apochromatic lenses. That’s why maneuvering them is a bit easier. It’s similar to how scope or stellina telescopes work.

Color Accuracy

Apochromatic telescopes produce sharp and more color-accurate photos. Since it’s manufactured in advanced processes, the wavelengths align perfectly with the focal point. 

This improves the color contrast and the image’s sharpness. The lens also reduces eye strains, unlike other telescopes. 

These are the reasons why apochromatic telescopes are the best option for stargazing. You’d see the difference if you compared the images from both telescope types. For example, apochromatic telescopes can capture astronomical photos better and with more details.

Compared to apochromatic, achromatic telescopes need to catch up regarding image compatibility. Achromatic telescopes provide filters that minimize the color fringes. Even with the top-notch nebula filter, apochromatic telescopes might be more accurate. 

Although the lens doesn’t take accurate photos like apochromatic telescopes, it can still make stellar images for astronomical research. 

The color accuracy level might not be as clear as apochromatic. But it’s still ideal for the moderate-budget telescope.


Apochromatic telescopes are more expensive than achromatic telescopes. This is mainly due to having more lenses in the apochromatic telescopes. 

These lenses that come from different types of glasses are expensive to gather. Since it has many optical options, the price gets higher.

Achromatic telescopes are cheaper. They don’t contain as many lenses as apochromatic telescopes—only a convex and concave lens. The body is also smaller and doesn’t contain various optical options. That’s why they are cheaper. 

The following achromatic telescopes are budget-friendly and also of good quality-

Product 1
Product 2

Final Decision: Apochromatic Vs. Achromatic

Choosing a telescope initially depends on what requirements you want in your telescope. The apochromatic and achromatic have a big difference in quality and price. If your budget is bigger, you should go for an apochromatic telescope. 

However, this doesn’t mean achromatic telescopes are bad. They are quite good depending on the price it offers. But we must declare the apochromatic telescope as the winner in this discussion.

I hope this discussion was helpful to you.


Question: What does APO mean on lenses?

Answer: APO stands for the apochromatic lens. It’s a photographic lens that has better spherical aberration and chromatic correction. Standard lenses don’t have such features.

Question: How to know if the telescope glasses are worth your money?

Answer: Before buying a telescope, get a basic idea about them. Be brand-specific, depending on the quality you’re looking for. Please pay attention to the glass quality as it’s important in telescopes. It’s better If it has any special coatings such as dielectric or phase correction.

Question: Why are fluorite glasses used in APO telescopes?

Answer: Fluorite glasses have a very low dispersion rate. It doesn’t dissipate the light waves when it reflects on the glass. It helps the lenses to reduce chromatic aberration. That’s why it’s used in APO telescopes.


So, how was our discussion regarding the differences between apochromatic and achromatic? Hopefully, it was informative for you. 

I look forward to seeing you in another optic discussion.

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