Meade ETX-90 Review: Specs & Astronomy Performance

Telescope set up for outdoor observing — Image Credit: Kazuend

The Meade ETX-90 is a compact 90mm Maksutov-Cassegrain telescope with a 1250mm focal length that appeared in several versions during its long production history. First introduced in 1996, the ETX-90 subsequently evolved through a number of mount and electronics configurations.

That distinction is important because an original ETX-90 and later versions such as the ETX-90EC, Premier Edition and Observer share the same basic 90mm Maksutov concept, but their mounts, electronics, controllers and supplied accessories can differ substantially.

The underlying optical design is particularly suited to the Moon, planets, double stars and other relatively compact targets. Its long focal length provides useful magnification in a physically short optical tube, while the trade-off is a narrower field of view than a short-focal-length refractor.

Which Meade ETX-90 Version Do You Have?

The ETX-90 name was used for several generations of telescope, so identifying the version is important because the mount, electronics and supplied accessories changed considerably over the telescope’s production history.

The original ETX-90, introduced in 1996, used a motorized fork mount but did not have the computerized GoTo system associated with later models. The ETX-90EC, introduced a few years later, added electronic control and could be paired with Meade’s Autostar controller for computerized object locating.

Later versions included models such as the ETX-90 Premier Edition and ETX-90 Observer, with further changes to the electronics, controllers and supplied accessories. As a result, features such as GoTo operation should not be assumed simply because a telescope carries the ETX-90 name.

When researching an ETX-90, it is therefore worth checking the exact model designation, hand controller and mount configuration rather than relying on specifications for another generation.

90mm Maksutov-Cassegrain Optics

At the heart of the ETX-90 is a 90mm Maksutov-Cassegrain optical system with a 1250mm focal length, giving it a focal ratio of approximately f/13.9. The folded optical path allows that long focal length to fit inside a remarkably compact optical tube.

This combination naturally favors lunar and planetary observing. The long focal length makes useful magnifications relatively easy to achieve, while the Maksutov design is also well suited to compact targets such as double stars.

The 90mm aperture can also show brighter star clusters, nebulae and some galaxies under suitable conditions, but deep-sky observing is not the ETX-90’s main strength. Its relatively small aperture limits light gathering, while the long focal length produces a narrower field of view than a short-focal-length refractor.

GoTo and Tracking on Later ETX-90 Models

Computerized operation became an important feature of later ETX-90 models, but the exact system depends on the version. Models equipped for Meade’s Autostar or later AudioStar controllers could automatically slew toward selected objects after the telescope had been correctly set up and aligned.

Once an object was located, the motorized fork mount could track its movement across the sky, reducing the need for constant manual adjustments. This is particularly useful when observing the Moon and planets at higher magnifications, where objects otherwise move through the eyepiece relatively quickly.

GoTo does not remove the need for setup, however. The telescope requires a suitable power source and accurate initial alignment before its computerized locating and tracking functions can be used.

The capabilities of the specific ETX-90 version should therefore be checked rather than assuming that every model includes the same computerized functions.

What Can You See Through an ETX-90?

The Moon is one of the ETX-90’s strongest targets. Its 1250mm focal length makes it easy to reach useful magnifications for examining craters, mountain ranges, lunar maria and the changing shadows along the terminator.

The bright planets are another natural match for the telescope. Jupiter’s four Galilean moons and main cloud belts are within reach, while Saturn’s rings can be clearly distinguished from the planet itself. Venus shows its changing phases, and Mars can reveal some surface detail when it is relatively close to Earth and atmospheric conditions are favorable.

Beyond the Solar System, the ETX-90 can be used for double stars, brighter open clusters, planetary nebulae and some of the brighter galaxies and nebulae. Its 90mm aperture and relatively narrow field of view make faint or very large deep-sky objects more challenging.

This makes the ETX-90 better suited to observers interested primarily in the Moon, planets and other compact targets than those wanting wide views of large star clusters or extensive Milky Way star fields.

Limitations to Consider

The ETX-90’s 90mm aperture is its most obvious limitation. It is sufficient for useful lunar and planetary observing, but it gathers considerably less light than larger telescopes, restricting what can be seen in faint galaxies, nebulae and other deep-sky objects.

Its 1250mm focal length also produces a relatively narrow field of view. This suits planets, double stars and other compact targets, but large open clusters and wide Milky Way star fields are better matched to shorter-focal-length telescopes.

Computerized ETX-90 versions also introduce more complexity than a simple manual telescope. Power and initial alignment are required for GoTo and tracking, while the motors, electronics and hand controller add components that are absent from a purely manual mount.

The exact ETX-90 version is therefore important when assessing the telescope, but the underlying strengths remain its compact Maksutov design, long focal length and suitability for lunar and planetary observing.

Who Is the Meade ETX-90 Best For?

The Meade ETX-90 is best suited to observers who want a compact telescope primarily for the Moon, planets, double stars and other bright, relatively small targets. Its 90mm aperture and long 1250mm focal length make it less suited to faint deep-sky objects and very wide-field observing, while the exact convenience of its mount and computerized features depends on which ETX-90 generation you own.