Celestron C90 Mak Review

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If you thought that Celestron only made high quality telescopes, think again. Now, they are back with a high powered lineup of excellent spotting scopes for you to choose from. The Celestron C90 Mak is a compact and powerful spotting scope that uses the same technology they put in their high grade telescopes to deliver you a chart topping spotting scope.

I was surprised at both the overall quality and level of versatility that this scope offers. It is not only a premium spotting scope but can also be used for a variety of photography activities and even as a casual telescope. If you are someone looking for a versatile spotting scope that can be used in all manner of ways, then the C90 Mak should definitely be on your radar.

  • Type: Maksutov-Cassegrain
  • Aperture: 90mm
  • Field of view: 1.3°
  • Field of View (feet @ 1000yds): 67’
  • Close focus distance: 15’
  • Lens coatings: Multi-coated
  • Weight: 5lbs

The sheer amount of uses that I could come up with for this spotting scope really surprised me. I am very familiar with Celestron’s telescopes but less so with their spotting scopes so when I dug into the details of it’s design and construction I didn’t know what to expect. What I found was a super pleasing array of features that make this one of the most well-rounded scopes I’ve ever used.

Celestron C90 Mak Review
  • Super lightweight and portable
  • Great size
  • Powerful, clear optics
  • Extremely versatile
  • Not super durable
  • Not waterproof
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I can see this scope being an instant purchase for anyone who has a list of diverse outdoor activities they enjoy or for the outdoor spotter or photographer looking to snap some great pictures out in nature.

Let’s get down to it.

Why A Spotting Scope?

What gives? Isn’t this a telescope website? Yes, yes it is. However, spotting scopes can double as effective telescopes as well as offering a wide array of other options for use.

At their cores, spotting scopes and telescopes are very similar in their design and uses. The main difference between the two is the inclusion of an internal erect image diagonal in the spotting scope and that spotting scopes generally have lower magnification levels than telescopes.

The erect image diagonal makes it so all of the images appear right side up when they are in the eyepiece. Most people do not know that without this handy gizmo, telescopes usually display their images upside down or rotated ninety degrees. That doesn’t matter much when viewing a galaxy thousands of lightyears away but will make trying to get a good bead on a deer a lot more difficult.

If you are merely interested in simple backyard astronomy, you might not want to dig into a spotting scope. But if you have a wider range of activities that you enjoy, a spotting scope might be a great fit for you.

Where they lack in magnification power, spotting scopes make up for in size and focus.

Bonafide Great Optics

As a scope, the most important part is going to be the optical quality. I can confidently say that the optics on this scope are fantastic. Celestron has taken their years of experience and used it to craft a wonderful example of terrestrial optics. The images are clear, sharp and easy to focus. There are no chromatic aberrations, something that often plagues cheaper scopes. With a lot of sunlight, you get a lot of opportunity for wayward light messing up your images. I saw none of that with this scope.

The included eyepiece gave you a good middle ground for a spotting scope coming in at around 40x magnification. This is a great level for terrain spotting, bird watching and hunting. It is also a great magnification level for certain kinds of photography.

The glass in this scope is all multi-coated. You can tell that the glass and coatings are of high quality at first glance. First, you can see the coatings on the lens giving off that classic look of a high grade piece of optical equipment. That is what cuts down nearly all of the aberrations giving you crystal clear images in all light levels.

Normally, you do not get such clear concise images out of a scope of this size. The aperture on this scope is a solid 90mm giving you ample opportunity for both daytime land viewing as well as solid night viewing as well. It comes in at just over a foot in length and weights just under five pounds. They get this level of quality and performance out of a such a squat statured scope due to its proprietary design.

Celestron describes it best.

“The Maksutov-Cassegrain design of the C90 uses a combination of mirrors and lenses; this folded optical system has a focal length of 1250mm in a body only twelve inches long.”

The result are super high grade optics in a truly small package which gives you a powerful tool that won’t weigh you down.

Truly Portable

The tiny size of this scope really makes it a portable option. In fact, it barely takes up more space than a solid pair of binoculars. For anyone who wants to take the optical power of Celestron with them out into the world, you will not find a better scope in which to do it with.

It is not just small, it is designed to be taken out and about. It sports a folding eyecup and an included cover which allows you to easily fold this scope, cover it and take it with you.

Other portable scopes are a lot smaller, with apertures half the size of this one or are low quality hand held scopes that cannot hold a candle to this scope.

Supreme Versatility

This truly is one of the most versatile scopes I have ever worked with. And it is not even close. Celestron has gone out of their way to ensure that this scope can be used in almost every conceivable way. If you have an idea for what you would use a scope like this for, I’m sure at the C90 Mak can do it.

How is this possible?

First, it is completely compatible with all 1.25” eyepieces. That includes any photography or astronomy eyepieces that are configured to fit the universal 1.25” hook up. This opens up a whole world of accessories and eyepieces that can really flesh this scope out.

That means you can add a 5mm eyepiece or a 25mm eyepiece and get a wide range of magnification out of the optics. You can eke out 200x magnification for astronomy purposes with a telescope eyepiece or get a low powered eyepiece for specific nature observations.

This scope has a very generous close focus distance of 15’ which allows you to get excellent low powered magnification as well as high powered magnification.

It has dual mounting options featuring both a dovetail and threaded option. This means it can be mounted to almost any tripod on the market. You can throw it on your camera tripod for excellent photography spotting or hook it onto your existing telescope tripod. Either way it will be at home.

Between the dual mounting option and the 1.25” astronomy compatible eyepiece hook up you can kit out this scope to do almost anything you can put your mind to.

It also has a SLR camera ready lens which allows you to easily hookup your digital camera to this scope creating a massive 1250mm lens. This can open up a whole new field of photography to try out including animal, nature, astro and landscape photographs.

The obvious uses for this scope are many and varied. Take it hiking with you to get some mountaintop views after the end of a long day. Take it camping out to a dark sky area and get close up shots of the moon, stars, and planets. You can use it as a hunting scope to keep an eye on things from your blind or baited field. Also, you can use it for nature or landscape photography. You can use it for astrophotography. You can use it to spot distant planes or trains, if transport spotting is your thing. It can be used for birdwatching.

I am positive that there are some not so obvious uses that the creative or adventurous person could also discover for this scope. It really can do it all.

Accessories Included

Plus, it comes with some great accessories as well. A scope cannot be truly great without the inclusion of some fun accessories to spice it up. Celestron knows this well and has added all of the basics you will need to get started.

The Celestron C90 Mak comes with a custom backpack case, 32 mm eyepiece, 45° erect image diagonal 8×21 mm erect image finderscope, objective cover, cleaning cloth, and instruction manual. All of these extras come included, no extra cost. They are more than enough to get you started.

The diagonal, as mentioned, ensures the images appear correctly in the eyepiece. The single eyepiece offers 39x magnficiation which is a good medium powered eyepiece for general use. The cover, backpack case and cloth all will help you to keep your scope in tip top shape without having to buy any additional items in that department. The finderscope makes it easy for you to dial in your optics and spot objects easier.

All of this can be easily packed away in the included backpack for ideal storage and transport. This is a nice touch since many scopes do not come with a case, however this does come at the expense of a tripod which is not included.

The exclusion of a tripod is only one of a couple of minor issues with this scope.

A Few Drawbacks

Unfortunately, nothing is perfect. While the output of this scope can’t be argued with, there are a few things that hold it back. First, this scope is not waterproof. It comes with a bag, an objective cover and a cleaning cloth but those things only serve to try and keep the moisture at bay for so long. This scope is not waterproof which means it cannot be confidently taken on a boat or by any large bodies of water. While this isn’t a huge deal, it does somewhat limit the full range of travel that you can do with it.

I would also be hesitant to leave it outside for any reason or let it sit while you’re camping or hiking. If condensation or water gets into the fragile innards of this scope, it can play havoc with the image quality causing fogging or distortions which is unfortunate.

Speaking of the innards, the other issue is that this scope is not as durable as some other scopes on the market. The unique “folded” internal optical system that keeps the size down and the quality up is also more fragile than competing scopes. Some people have reported baffles that are out of alignment and mirrors that if banged out of position can ruin the internal optics of this scope.

That means that you have to be more careful when taking this scope into bumpy situations and it is not entirely stress-free to travel with this scope.

This scope also only comes with a single eyepiece included meaning that to get the full range of options out of the Celestron C90 Mak you will have to buy some additional eyepieces. Luckily, there are kits out there that are fairly inexpensive but the additional cost might put some people off.

Other than that, this is a solid scope that if taken care of properly can give you years of spotting enjoyment.


All in all, if you are looking for a spotting scope that can do it all, this is the scope for you. If you can think of a use for a spotting scope, the Celestron C90 Mak makes it into our Spotting Scope For Astronomy will give you its best effort to try and achieve it. With tons of versatile uses and nearly unlimited potential for accessories and custom setups, this is a scope that needs to be on any outdoorsman’s mind.

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