Maksutov Newtonian Telescopes (In-depth Guide)

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Maksutov Newtonian is a combination of the Newtonian reflector and Maksutov correcting lens. Standard Newtonians suffer from coma around the edge of the field of view. The Maksutov corrector plate is correcting this coma and producing coma-free stars across the field. It also corrects the spherical aberration of the primary mirror.

Maksutov Newtonian is a rare and unique design in the telescope world. It is not so popular, but it is starting to gain the traction it deserves.

They typically have aperture sizes ranging from 150 to 190 mm. Despite the large aperture size, they are significantly cheaper than apo refractor telescopes of the same size. The Maksutov Newtonian telescopes are heavier, though.

Anyone who’s used a Maksutov Newtonian telescope will tell you it excels exceedingly well for astrophotography, though it is also great for visual astronomy. 

In this guide, I’ll share in-depth details about its specifications, what it is used for, its advantages over standard Newtonian telescopes, if it’s worth investing in, a few recommended examples, and much more.

Specifications of Maksutov Newtonian telescopes

Most Maksutov Newtonian telescopes come with an aperture size between 150mm to 190mm, although Intes-Micro produces Mak-Newt telescopes with aperture sizes from 127 to 305mm. 

The focal lengths of Mak-Newt telescopes vary depending on the targeted focal ratio. Most Mak Newtonian designs are fast scopes with focal ratios between f/4.8 to f/8 maximum. 

The diameter of the secondary mirror can range from 26mm to 64mm. They can weigh anywhere between just over 15 pounds to over 40 pounds. 

The material used for the tube significantly determines the weight of the scope. Always choose a tube assembly made with carbon fiber, where available. 

What is a Maksutov Newtonian telescope used for?

A Maksutov-Newtonian telescope is typically used for astrophotography and observing deep-sky objects with high contrast and sharpness. They require no field flattener, focal reducer, or a coma corrector like a standard Newtonian telescope would. 

Just attach a camera to it, and it’s good to go. One of the reasons they do well for astrophotography is the high contrast they offer and the relatively broader field of view. That said, they are also good for just observing the night sky. 

It’s also worth pointing out that some manufacturers intentionally design some Maksutov Newtonian telescopes for planetary and lunar observations rather than faint deep sky objects. 

A great example is the 6-inch aperture Macksutov-Newtonian telescope by Intes-Micro, which has a focal ratio of f/8. 

Is a Maksutov Newtonian better than a standard Newtonian telescope?

The Maksutov Newtonian is better than a standard Newtonian telescope primarily because the former does not produce diffraction spikes. Balance-wise, the Mak-Newtonian offers better balance on mounts than standard Newtonians. 

Compared to the standard Newtonian telescopes, Mak-Newtonian scopes are easier and quicker to collimate. 

What is Coma in a Newtonian telescope?

Source: Vik Dhillon

Coma refers to an optical aberration that causes off-axis light to form a comet-like tail. An imperfect mirror shape causes a coma in the reflector, meaning you see deformed stars around the edge of the field of view. 

The stars are elongated and look like small comets – dots with a tail. 

Coma is present in all Newtonian reflectors, but you can fix it with a coma corrector screwed onto the eyepiece or a camera. So even if you have a more expensive parabolic mirror in your telescope, you still need a coma corrector.

The coma is not really an issue for serious visual observers. In astrophotography, it is a problem, and you need to correct it. 

With the cheaper spherical mirror in the Maksutov Newtonian, there’s no spherical aberration. It is coma-free because all this is already corrected with a single Maksutov corrector lens.

What is the Maksutov corrector lens?

Maksutov Corrector lens is a multi-coated spherical lens with an equal but opposite spherical aberration to the spherical primary mirror. This lens corrects the spherical aberration and the coma. It uses a meniscus corrector plate instead of the complex Schmidt corrector plate. 

When light travels through the lens, it is refracted, hitting the primary mirror at the right angles to produce a crisp image. That’s why you don’t need other correcting equipment with the Maksutov Newtonian telescope.

But manufacturing the correcting lens is not easy for bigger apertures. As a result, the Maksutov Newtonian is more expensive. You may ask why not use a standard reflector with a parabolic mirror and use the coma corrector instead. Well, a high-quality coma corrector can cost hundreds of dollars.

The Maksutov correcting lens is made exclusively for the given telescope, so the image is much better in the Maksutov Newtonian than in the standard reflector with a coma corrector.

Difference between Maksutov Newtonian and Maksutov Cassegrain

Don’t get mistaken. The Maksutov Newtonian is not the Maksutov Cassegrain. The correcting lens and mirrors are the only things they share in common. The Maksutov Newtonian design is completely different.

The Maksutov Cassegrain telescope features a catadioptric design comprising a spherical primary mirror with a central aperture and a convex secondary mirror. Something like the reflector, but the light path is different. The light travels through the optical tube, then it is reflected by the primary mirror to the secondary mirror that is flat to the primary mirror.

The secondary mirror reflects the light into the hole of the primary mirror where the eyepiece is installed. The light travels twice as much as in a reflector, and the convex curvature of the secondary mirror magnifies the focal length further. 

It results in a very long focal length but also a very short optical tube.

Read more: Schmidt Cassegrain vs Maksutov Cassegrain (Comparison)

Mak-Newtonian has a standard reflector design with a primary mirror and 45 degrees-tilted secondary mirror at the front of the optical tube. But because it uses a spherical primary mirror, it suffers from spherical aberration.

That’s why it is equipped with the Maksutov correcting lens. Standard reflectors use a more expensive parabolic mirror that is free of spherical aberration, but they also have the issue of coma.

Advantages of the Maksutov Newtonian

There are a few advantages of the Maksutov Newtonian over the standard reflector. As I mentioned, the lens is built to perfection for a given telescope. The big difference is that the convex secondary mirror is not spider mounted at the front of the optical tube.

On the Maksutov Newtonian telescope, the secondary mirror is mounted on the correcting lens itself. Hence no diffraction spikes.

However, some astronomers like the diffraction spikes on the stars, and some astrophotographers using refractors add diffraction spikes to their photos when processing the image manually.

The next advantage is the balance of the OTA. The correcting lens adds more weight to the front of the tube, creating a good balance.

The standard reflector is heavy at the rear with the primary mirror only, and you have to push it a little bit forward when balancing the OTA on the mount. 

Maksutov Newtonian is easier to balance on the mount because the weight is distributed between the primary mirror at the back and the correcting plate at the front.

Another advantage which is also a disadvantage (oxymoronic, yeah?), is that it is a closed system. It’s great that you don’t have to worry about the dust in the optical tube.

On the other hand, it will take much longer to equalize the outside temperatures thermally. And it will take increasingly longer with the bigger apertures. So yes, it is a little drawback.

Ensure you take your telescope out long enough before the observing or shooting session.

Is the Maksutov Newtonian good for astrophotography?

The Maksutov Newtonian is primarily made for astrophotography. It’s the field where it excels. The optical design in Maksutov-Newtonian telescopes provides high speed, exceptional field correction, and a lack of spherical aberration and coma, which make it a great option for astrophotography. 

Although you can also use it for visual astronomy, you just need to use an extender with the eyepiece to reach the focus. The extender usually comes with a telescope, so you don’t have to buy it separately.

The majority of scopes used for astrophotography are refractors for many reasons. But the reflector astrophotography community is also strong. And then, there is something in the middle, the Maksutov Newtonian astrograph.

There are many reasons why the refractor group is big, but the Maksutov Newtonian is a reflecting telescope that is refractor-like, if you know what I mean. These scopes were born to do astrophotography with pinpoint stars across the field and coma-free sharp images.

They also have a small focal ratio, so they are pretty fast scopes gathering light faster than slow refractors. Because of this, you are okay with shorter exposures and will collect the same data as a slow refractor with a longer exposure time.

And there is also the price. Yes, they are more expensive than a typical Newtonian reflector. 

However, if you want a top-quality ED Apochromatic refractor for astrophotography, the Maksutov Newtonian is a much cheaper option for a given aperture size.

You may also like: Refractor vs Reflector Telescope: What Is The Difference?

Best Maksutov Newtonian Telescopes

There are few manufacturers on the market making excellent Maksutov Newtonians like SkyWatcher, Orion, or Explorer Scientific. 

Here is a detailed description of these models:

1. SkyWatcher 190mm Maksutov Newtonian telescope

The Skywatcher Explorer 190mm Maksutov-Newtonian telescope has a very small central obstruction and is equipped with five internal tube baffles that provide a high-contrast image by preventing stray light from reaching the primary mirror. 

You can liken its visual output to similar large aperture apochromatic performance telescopes. 

It has a wide field of view because of the small focal ratio of F/5.3 with a focal length of 1000mm.

This telescope is equipped with high-quality accessories. There’s a 2-inch Dual-Speed Crayford focuser that you can attach cameras to. It supports both DSLR and charged-coupled devices (CCD). 

Then you have the Vixen-style dovetail plate that allows you to attach the telescope to any mount of choice. It also includes a right-angle finderscope and is fully multi-coated. 

2. Orion Premium 190mm Maksutov Newtonian Astrograph Telescope

The Orion Premium 190mm Maksutov Newtonian Astrograph telescope has similar optical specifications as the Skywatcher Explorer. That is a focal length of 1000mm and a fast f/5.3 design. 

The similarities go beyond the optical specifications. The Orion Premium Mak-Newt telescope also has five internal baffles for good contrast. 

It comes with the same 2-inch Crayford-style focuser, but there’s an additional T-thread adapter that you can use to attach a camera to the focuser.

While the Skywatcher Explorer comes with a 50mm secondary mirror, the Orion Mak Newt telescope has a diameter of 64mm. 

The Explorer will perhaps have more contrast, but the extra diameter in the Orion telescope is great for field illumination and less vignetting. This feature makes the Orion a better choice if you have an APSC DSLR camera. 

3. Explore Scientific David H. Levy Comet Hunter

The Explorer Scientific also makes an excellent scope called the David H. Levy Comet Hunter with a carbon fiber tube. It is much lighter (about 3.6 pounds) but lacks internal baffles and other features compared to the SkyWatcher. Less weight equals less stress on your mount. 

The carbon fiber has other advantages aside from making the telescope lighter. It also provides better thermal equilibrium for the optical elements in the telescope. 

Once it reaches the cool-down temperature, it’s hard for a temperature change to lead to a shift in the focal plane. 

If you don’t have an electronic auto focuser, this should be a big deal for you. 

The telescope’s specifications are an aperture size of 152mm (5.98 inches), a focal length of 731mm (28.77 inches), a focal ratio of f/4,8, and a secondary mirror diameter of 64mm. 

Is it worth investing in a Maksutov Newtonian telescope?

Maksutov Newtonian telescopes have efficient designs tailored to astrophotography, which makes them a good investment for anyone highly interested in this hobby. Maksutov Newtonian are way cheaper despite their incredible contrast and optical quality, in comparison to apo achromatic refractor telescopes, 

Mak-Newt telescopes are also easy to use and collimate. Collimation is one of the big reasons many people opt for refractors when choosing telescopes for astrophotography. 

Also, the smaller corrector plate in Maksutov Newtonians leads to less obstruction than Schmidt Cassegrain corrector plates, which enables it to eliminate coma errors and flatten the field. 

So, you won’t need to invest in accessories like field flatteners, focal reducers, or a coma corrector like you would with a typical Newtonian telescope. 

These advantages are worthy reasons to invest in Mak-Newtonian telescopes if you ask me. 

Takeaway: Maksutov Newtonian Telescopes are highly effective tool in astrophotography

For beginners in astrophotography weighing the decision between buying a refractor or reflector, the Maksutov-Newtonian telescope provides a great middle-ground option.

They are remarkably better than standard Newtonians and great alternatives to apo refractor telescopes, price-wise, despite their weight.

It has the advantages of both refractors and reflectors. This type of design is the ultimate astrophotography telescope. If the need for collimation keeps you away from reflecting telescopes, Maksutov Newtonian scopes are easy to collimate. 

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