What is the Difference Between a Newtonian and Refractor Telescope?

If you’re someone who’s into astronomy and stargazing like me, you might have come across two types of telescopes, the Newtonian and the refractor. And if you’re anything like me, you might have found yourself wondering what sets these two types of telescopes apart and which one would be the better option for your stargazing adventures. In this article, we’ll discuss the difference between these types of telescopes so that you can make a more informed decision when it comes to your next telescope purchase.

So what’s the difference between a Newtonian and refractor telescope? Well, to put it simply, the main difference lies in the way they collect and focus light. A Newtonian telescope uses a curved primary mirror to gather and reflect light to a smaller, flat secondary mirror, which then reflects the light to the eyepiece. A refractor telescope, on the other hand, uses a lens to gather the incoming light and refract it to a focus point where the eyepiece is placed. This difference in design affects the way the two telescopes perform in terms of image quality, portability, and ease of use.

Now, you might think that the difference in design and the way light is gathered and reflected would make one of these telescopes decidedly better than the other. But as with most things, the choice largely depends on what you’re looking for in a telescope. In the following paragraphs, we’ll delve deeper into the specifics of each type of telescope and what they offer, so that you can make an informed decision when it comes to buying your next stargazing tool.

Newtonian Telescopes

A Newtonian telescope is a reflector telescope that uses a curved primary mirror to gather light and reflect it towards a smaller, diagonal secondary mirror. The secondary mirror then reflects the light through an opening called the focuser, where the eyepiece is attached. This design was invented by Sir Isaac Newton in the 17th century and is the most popular type of reflector telescope.

The advantages of using a Newtonian telescope include:

  • Better image quality and sharpness as compared to a refracting telescope because they do not suffer from chromatic aberration, which is caused by the bending of different colors of light at different angles.
  • Newtonian telescopes typically have a larger aperture (the diameter of the telescope’s primary mirror) for a given price, which means they can collect more light and reveal fainter objects in the sky.
  • They are less expensive than refractor telescopes of the same size and quality.

On the other hand, there are also some drawbacks of using a Newtonian telescope:

  • Collimation, which is the alignment of the mirrors, needs to be regularly checked and adjusted to maintain optimal image quality. This can be a complex and time-consuming process for beginners.
  • The diagonal secondary mirror can sometimes cause light loss and reduce contrast in the final image.
  • They are typically larger and bulkier than refractor telescopes of the same aperture size, making them more difficult to transport and store.

If you are looking for a telescope primarily for visual observing of bright objects like planets, galaxies and star clusters, a Newtonian telescope is an excellent choice. They offer excellent image quality, good aperture for the price, and are the most affordable large-aperture telescopes available. However, if you are interested in astrophotography, refractor telescopes may be a better option due to their relatively simpler design and their ability to image deep-sky objects with less maintenance required.

Refractor telescopes

One of the most common types of telescopes is the refractor telescope. This telescope uses lenses to gather and focus light. The lens at the front of the telescope is called the objective lens and it gathers light from the distant object being viewed.

Refractor telescopes have some unique advantages and disadvantages:

  • Advantages:
    • They have a sealed tube that protects the optics from dust and other debris.
    • They are easy to use and require very little maintenance.
    • They provide a crisp, clear image with excellent contrast.
    • They can be used for both terrestrial and astronomical viewing.
  • Disadvantages:
    • They are typically more expensive than reflector telescopes of the same aperture.
    • They suffer from chromatic aberration, which causes color distortions around the edges of the image. Some refractors use special types of glass to minimize this effect.
    • They may have a smaller field of view than reflector telescopes.


When it comes to telescopes, the optics are the most important aspect to consider. The quality and type of optics will determine the clarity and accuracy of your view of the night sky. Both Newtonian and Refractor telescopes use different types of optics, which affect their performance in different ways.

Optics in Newtonian vs Refractor Telescopes

  • Newtownian telescopes use a parabolic mirror, which reflects and focuses the light to produce an image. The shape of the mirror allows for a wider field of view, which means you can observe more of the night sky. However, the mirror is not able to correct for chromatic aberration, which can lead to color fringing around brighter objects.
  • Refractor telescopes, on the other hand, use a lens to focus the light. The lens is able to correct for chromatic aberration, which means you won’t see any color fringing around bright objects. However, the design of the lens limits the field of view, which can make it difficult to observe larger objects in the night sky.

Optical Quality

Another important factor to consider when it comes to optics is quality. Both Newtonian and Refractor telescopes come in a variety of qualities, which can affect their performance. A high-quality Newtonian telescope can provide exceptional clarity and sharpness, while a lower quality one may produce a softer image.

Similarly, a high-quality Refractor telescope can offer excellent contrast and detail, while a less expensive one may have issues with spherical aberration, which can cause objects to appear distorted or blurry.

Choosing the Right Telescope

Telescope Type Pros Cons
Newtonian Wide field of view, excellent for observing deep sky objects, affordable May have issues with chromatic aberration, needs regular maintenance to keep the mirror aligned
Refractor Excellent for observing planets, corrects for chromatic aberration, requires less maintenance Limited field of view, more expensive for higher quality models, more fragile due to long tube design

Ultimately, your decision on which type of telescope to choose will depend on your specific needs and preferences. Consider what objects you want to observe, as well as your budget and level of maintenance comfort.

Whichever type of telescope you choose, be sure to invest in a high-quality lens or mirror for the best possible viewing experience.

Light Gathering Capability

One of the most important factors to consider when choosing between a Newtonian and Refractor telescope is the light gathering capability. This refers to how much light the telescope can collect, and therefore, how clear and bright the images will appear.

When it comes to light gathering capability, the Newtonian telescope is the clear winner. This is because it has a larger aperture (the opening through which light enters the telescope) compared to a refractor telescope of the same size. A larger aperture means more light can enter the telescope, resulting in brighter, sharper images.

  • A larger aperture means better resolution and more detail in the images.
  • Newtonian telescopes are better for deep-sky observations, such as nebulae and galaxies.
  • Refractor telescopes are better for observing planets and the Moon.

Here’s how the light gathering capability of a Newtonian and Refractor telescope of the same size compare:

Telescope type Aperture Light gathering capability
Newtonian 8 inches 843 times more light than the human eye
Refractor 8 inches 513 times more light than the human eye

As you can see, even at the same size, the Newtonian telescope can gather significantly more light than the Refractor telescope, resulting in better images.


Magnification is, without a doubt, one of the most significant factors in telescope selection. The power of your telescope is equal to the number of times the image it captures has been magnified. This is frequently expressed as a two-digit number (e.g., 25x). The first digit specifies how many times more significant the object appears than to the naked eye, while the second indicates the caliber of the lens or mirror utilized to accomplish this effect.

Magnification is not something that should be overvalued since it is dependent on a variety of other equally important factors, such as lens or mirror size, light-gathering ability, and atmospheric conditions. The rule of thumb for magnification is that it should not be more significant than twice the lens or mirror diameter in millimeters. In addition to these factors, the type of telescope you choose will also affect your magnification experience.

Newtonian vs. Refractor Telescope Magnification

  • Newtonian telescopes provide greater magnification because of their longer focal length, which stretches the light further before it reaches the eyepiece. They also have a wider field of view, allowing you to observe more objects in the night sky.
  • Refractor telescopes, on the other hand, are designed to minimize the chromatic aberration that causes false colors around objects, producing a more natural-looking image. They also require less maintenance and provide a more stable image because they have fewer moving parts.
  • Both telescopes have their strengths and weaknesses when it comes to magnification, depending on what you want to observe. Ultimately, the best telescope for you will depend on your personal preferences and what you hope to achieve with your telescope.

Magnification and Aperture

While magnification is an essential factor to consider when choosing a telescope, aperture is equally important. Aperture refers to the size of your telescope’s light-gathering lens or mirror, and it determines how much light your telescope can capture and focus. The larger the aperture, the more significant the objects you can observe and the more detail you will see.

The relationship between magnification and aperture is such that increasing magnification decreases the brightness of the image produced, which is why it’s essential to have a large aperture. A larger aperture will allow you to use higher magnifications with less loss of brightness.

Magnification Table

Telescope Magnification Range
Small refractors & Newtonians 25x-75x
Medium-size refractors & Newtonians 75x-150x
Large refractors & Newtonians 150x-300x
Giant refractors & Newtonians 300x-600x

Magnification is an important factor to consider when choosing a newtonian or refractor telescope. While each has its strengths and weaknesses in terms of magnification, ultimately, the choice comes down to personal preference and what you hope to achieve with your telescope. Remember that magnification is not the only factor to consider. Aperture, light-gathering ability, and atmospheric conditions are also essential to obtaining the optimum viewing experience.


Maintaining your telescope is important to ensure the longevity and quality of your viewing experience. Here are some maintenance tips for both Newtonian and refractor telescopes:

  • Keep the lenses clean and free of dust. Use a soft cloth or brush to clear any debris from the lenses, and avoid using water or harsh chemicals.
  • Check the alignment of the optical components. Make sure the mirrors and lenses are aligned properly for optimal performance.
  • Store your telescope in a dry and cool environment. Avoid storing it in areas with high humidity or temperature fluctuations.

Newtonian vs Refractor Maintenance

In terms of maintenance, there are some differences between a Newtonian and refractor telescope. Here are some points to consider:

Newtonian Maintenance:

  • The mirror on a Newtonian telescope may require more maintenance than the lens of a refractor telescope. Make sure to clean the mirror carefully, as any scratches or damage could affect the image quality.
  • Check the alignment of the secondary mirror, as misalignment can negatively affect the image quality. This is especially important for larger Newtonian telescopes.

Refractor Maintenance:

Refractor telescopes are generally low-maintenance, but here are some things to keep in mind:

  • Check the alignment of the lenses to ensure that they are properly spaced and aligned. Any misalignment can cause distortion in your image.
  • If you notice any scratches or damage to the lens, take it to a professional for repair. Attempting to fix it yourself could cause further damage.

Regardless of the type of telescope you have, regular maintenance is key to preserving the quality of your viewing experience. Following these tips will ensure that you get the most out of your telescope and enjoy the wonders of the universe for years to come.

Newtonian Refractor
Regular cleaning of primary and secondary mirrors. Regular cleaning of lenses.
Alignment of mirrors must be regularly checked. Alignment of lenses must be regularly checked.
May require collimation tools for accurate alignment. Less likely to require collimation tools.

As shown in the table above, there are some maintenance differences between Newtonian and refractor telescopes. However, with proper care and attention, both types of telescopes can provide incredible views of the cosmos.

Price Range

When it comes to telescopes, the price can range anywhere from a few hundred dollars to thousands of dollars. The price will depend on various factors, including the type of telescope, quality of optics, brand name, and additional features such as computerized mounts and tracking systems.

  • Refractor telescopes tend to be more expensive due to the high quality of optics needed to produce high-resolution images. Expect to pay around $500-$2000 for a refractor telescope.
  • Newtonian telescopes can be more affordable with prices ranging from $200-$1000 for a basic model without additional features.
  • Advanced Newtonian telescopes with advanced optics and computerized mounts can cost up to $5000.

It is important to remember that while price is a significant factor in making a decision, it is not the only factor. You should also consider other features such as the size and weight of the telescope, as well as the type of objects you want to observe.

Telescope Type Price Range
Refractor Telescopes $500-$2000
Basic Newtonian Telescopes $200-$1000
Advanced Newtonian Telescopes $1000-$5000

Ultimately, the price will depend on your needs and preferences. It’s important to do your research and find a telescope that provides the features and quality that you need while staying within your budget.

What is the difference between a Newtonian and Refractor telescope?

Q: What is a Newtonian telescope?
A Newtonian telescope uses a curved mirror to collect and reflect light back towards an eyepiece located on the side of the telescope.

Q: What is a Refractor telescope?
A Refractor telescope uses lenses to gather and focus light into an eyepiece at the end of the telescope.

Q: What is the main difference between the two?
The main difference is the way they collect and focus light. A Newtonian telescope uses a mirror while a Refractor telescope uses lenses.

Q: Which one is better for viewing planets and galaxies?
A Refractor telescope is better for viewing planets and galaxies because it provides a clearer and sharper image due to the absence of obstruction caused by the secondary mirror.

Q: Which one is better for viewing deep space objects?
A Newtonian telescope is better for viewing deep space objects because it has a larger aperture which allows more light to enter the telescope, making faint objects brighter and easier to see.

Closing Thoughts

Thanks for taking the time to read about the differences between Newtonian and Refractor telescopes. Both types have their own unique advantages and disadvantages depending on what you want to observe. Consider your needs and preferences before choosing which one to buy for your stargazing adventures. We hope you find this information helpful and we welcome you to visit our site again for more informative content. Happy stargazing!