cassegrain vs newtonian

Cassegrain vs Newtonian- Which One To Choose?


The Newtonian and Cassegrain were among the first reflecting telescopes. These telescopes are widely used by astronomy enthusiasts. But from eyepiece placement to object type, they differ from each other in many factors. So it can be pretty tricky to determine which one’s perfect for you. 

Well, don’t worry. We’ve come to rescue you.

Which one to choose between, cassegrain vs newtonian?

The Newtonian telescopes give you a better aperture to price ratio. They‘re relatively cheaper and lightweight. The Cassegrain telescopes have convex secondary mirrors and bottom lying eyepieces. The Newtonian and the Cassegrain telescopes are more suited for viewing deep-sky and solar system objects, respectively.

The article has everything you need to know about the comparison between the Cassegrain and Newtonian telescopes.

Let’s jump into the main article.

Cassegrain vs Newtonian- Quick Overview!

In reflector telescopes, mirrors are used to collect and focus lights. Thus they’re chromatic aberration-free. But if you want to observe the Martian surface properly, you would need the Mars filter

However, they’ve many differences in working mechanisms and different properties. Let’s take a quick peek at their differences.

Parameter Cassegrain Newtonian
Secondary Mirror Convex mirror Flat mirror, inclined at a 45-degree angle
Eyepiece Located at the bottom part of the telescope Located at the top part of the telescope
Object Type Solar system objects Deep-sky objects
Weight Relatively heavier weight Lightweight
User Experience Somewhat harder to mount and imaging Easier to mount, easier imaging
Price A bit pricey Comparatively cheaper
Aperture-Price Ratio Not as good Better
Aperture-Body Ratio Better Not as good
Portability Relatively less portable More portable

Cassegrain vs Newtonian- Detailed Preview!

We know that the basic differences may have given you an idea. But you definitely need more details in order to choose one. Hence we’ve provided a detailed comparison down below-

Secondary Mirror

Cassegrain and Newtonian have different types of secondary mirrors. The Newtonian telescopes have flat mirrors, and they stay inclined at a 45-degree angle. 

On the other hand, the Cassegrain telescopes have convex mirrors in the place of flat mirrors. However, both of these telescopes have the same primary mirror, which is the concave parabola.

In Newtonian telescopes, light enters through the primary mirror. Then the secondary flat mirror directs it to the eyepiece. This mechanism works best for small-sized telescopes. 

In Cassegrain telescopes, light is reflected to the primary mirror’s center by the secondary convex mirror. Then the light is passed through a hole and goes to the focus behind the primary mirror. This gives the benefit of providing long focal length despite the increase in length of the telescope.


A high-quality eyepiece can determine your experience with the telescope. The eyepieces of the Newtonian telescopes are located at the top part. So if your telescope is a large one, you would need a stool to reach the eyepiece. There’s another problem with the Newtonian telescopes’ eyepiece. That is, they tend to move about frequently.

The Cassegrain telescopes have their eyepieces on the bottom part of the telescopes. It becomes challenging to look through the eyepiece if you’re a tall person. But if you use a tall mount, this shouldn’t be a problem.

Object Type

The Cassegrain telescopes are best suited for viewing objects within the solar system. This includes the planets and the moons of the solar system. The Newtonian telescopes, on the other hand, are more capable of showing you deep-sky objects.


The Newtonian telescopes tend to contain less glass as compared to the Cassegrain telescopes. That’s why the Newtonian telescopes are slightly lighter than the Cassegrain telescopes.

User Experience

When it comes to user experience, the Newtonian telescopes get a slight edge in a few parameters. These telescopes are easier to attach to the mount than the Cassegrain ones. Also, the imaging process of the Newtonian telescopes is a bit easier. It’s because of their shorter focal lengths than the Cassegrain ones.


In the price category, the Newtonian telescopes cost less than the Cassegrain telescopes. Once again, the reason behind this is the less glass used in the Newtonian telescopes.

Here are some of our favorite Newtonian and Cassegrain telescopes for you-

Product 1
Product 2

Aperture-Price Ratio

If you’re looking for the best aperture to price ratio, you should go for Newtonian telescopes. The aperture to price ratio of Cassegrain telescopes is not as great. The Newtonian telescopes are free of fake colors as well. Nonetheless, the Celestron Starsense series of these telescopes have some issues.

Aperture-Body Ratio

In the case of aperture to body ratio, the Cassegrain telescopes are the clear winners. They provide the same aperture at a relatively compact size. To get a large aperture, you’ve to choose a large model in the case of Newtonian telescopes.


As we mentioned before, the eyepieces of Newtonian telescopes are on the top portion. They’ve got small focal ratios as well. That’s why they require a smaller mounting system. A smaller mounting system means the Newtonian telescopes are more convenient to carry than the Cassegrain ones.

Final Verdict

Still haven’t decided? Let us help you then!

If you want a cheap, lightweight telescope for viewing deep-sky objects, go for Newtonian telescopes. Otherwise, go for the Cassegrain ones. Though they’re a bit expensive, you’ll get a great aperture at a compact size.

This was all we had about Cassegrain and Newtonian telescopes. We hope it made your decision a lot easier.


Question: What are the advantages of Newtonian telescopes?

Answer: The Newtonian telescopes give a wide field of view as they have short focal lengths. They’re also good at light gathering because of their fast focal ratios.

Question: What are the disadvantages of reflector telescopes?

Answer: There are inside air currents of reflector telescopes that can cause images to be fuzzy. To avoid this problem, the mirrors and optics should be kept at the same temperature as the outside air.

Question: Are refractor telescopes good?

Answer: The refractor telescopes are perfect for both terrestrial viewing and astronomy. They stay in shape easily, require less careful handling, and are less cumbersome.


Now that you know everything about cassegrain vs newtonian, you’re all set to go. We hope we could clear everything up for you.

Make sure to buy a sturdy mount for your telescope.

We wish you all the best.

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