Meade ETX-90: A Classic, But Don’t Buy the Wrong One!

Meade’s ETX-90 was a flagship of the company’s product line for decades. Offering high-quality Maksutov-Cassegrain optics in a portable and affordable package, the ETX-90 was originally designed to compete with the Questar, a widely revered premium telescope that continues to cost over $5,000 USD new. The Questar debuted in 1958 and has remained unchanged since. After a few failed attempts by Celestron, OTI, Bausch & Lomb, and Meade themselves to deliver a Questar-like telescope in the 1970s and 1980s, Meade came out with the original ETX-90 in 1996. The ETX-90 differs from these past attempts in two ways: the first is its use of Maksutov-Cassegrain optics like the Questar down to the exact same specs, and the second is its use of inexpensive materials, namely plastic, to cut on cost and weight. Celestron and OTI’s attempts were marred by the high cost of their all-metal fittings, while Meade/Bausch & Lomb attempted to sell 4” Schmidt-Cassegrains which were often of dubious optical quality, lacking the razor-sharp images the Questar (and now ETX-90) are known for.

By taking advantage of Meade’s ability to mass-manufacture precision telescope optics and parts, the company was able to reduce the price of the ETX-90 to about 1/10 of that (remaining steady with inflation) and add in features the Questar lacks, such as a DC clock drive by default and eventually full motorized GoTo. The only thing the ETX-90 lacks is the Questar’s built-in finder, which was one of the Questar’s greatest strengths; most ETX-90 models also lack a built-in Barlow lens like the Questar.

Like the Questar and other 90mm Maksutov-Cassegrains, ETX-90 isn’t for everyone, and it certainly over-promises somewhat in its advertising and packaging. The tiny 90mm of aperture and long focal length limit you to the Moon, planets, double stars, and brightest deep-sky objects. Astrophotography capabilities are negligible – the ETX-90 is useless for deep-sky imaging and is rather lacking in resolution for high-quality planetary images. And the electronic hand paddle supplied with the ETX-90 can often be a hindrance rather than a convenience, with jerky backlash-ridden movements, inaccurate GoTos, and of course, increasing setup time and power requirements. 

However, many people are very happy with their ETX-90s and you may find one to be the perfect fit for your telescope collection as a complement to larger instruments (though on its own it is bound to disappoint). The ETX-90 will blow away most small beginner telescopes on the Moon and planets and is really only rivaled in performance on these targets by expensive apochromatic refractors, larger Maksutovs, and SCT or reflector telescopes of at least 6” in aperture (nearly twice its size).

The ETX-90’s optics, basic design, and accessories have been fairly consistent throughout its existence, but other aspects have changed. We’re going to go over the broader features of the ETX-90 before diving into the specific versions, of which there are 5: the RA, EC, PE, Portable Observatory and Observer models.

The ETX-90 was available from 1996 to 2021 and discontinued in the wake of the COVID-19 pandemic, Orion’s lawsuit against Meade and their subsequent acquisition of the company. It is possible the ETX-90 or, indeed the entire line may make a return at some point, but at this time, it seems unlikely.

Similar Telescopes

In addition to the ETX-90, other Meade ETX models exist, though they were introduced later. The ETX-80 refractor is an 80mm f/5 achromat shoved onto the ETX mount and it works okay, though other wide-field refractors of similar specs outperform it. The ETX-60 and 70 use smaller lenses in the ETX-80 housing and are poor quality. The ETX-105 and 125 are larger Maksutov-Cassegrains; the 105 is seldom seen but excellent while the 125 can have issues on the stock fork mount but is a superb telescope. However, the ETX-90 has been around the longest, seen the most updates and is easily the most common of the “good” ETX telescopes (there may well be more 60s and 70s out there).

Numerous telescopes which duplicate or closely resemble the ETX-90 in form, function, and performance now also exist in addition to the Questar. The original Celestron C90, a 90mm f/11, was iffy in quality control and rarely sold on its (extremely heavy) fork mount which also required a very rare wedge to convert it to a usable configuration. However, the modern C90 is excellent, though it is only sold as an optical tube or on the Celestron NexStar SLT mount, the latter of which we don’t particularly recommend. The 90mm Maksutov-Cassegrain optical tubes sold by Sky-Watcher, Orion, and other brands are identical to the new C90. This includes the Sky-Watcher Virtuoso 90 package, which offers simple motorized tracking, a tabletop or tripod mount, and a compact form factor all at a rock-bottom price much like the ETX-90 did, though without the woes of laggy motors or a complicated AutoStar setup.

Larger Maksutovs made by Celestron’Sky-Watcher’s parent company Synta are also available up to 180mm in aperture – including the Celestron NexStar 4SE, whose predecessor, the 4GT, was originally created as an ETX-105 competitor and sports many of the same features, albeit in a bulkier package. The Celestron Astro Fi 102 shares the 4SE’s optics but not its flip mirror or mount design, but it’s a superior choice nonetheless. Numerous Maksutov-Cassegrain telescopes from Russia also resemble the ETX line in optical quality and surpass it in build quality, though many were sold without a mount.

If you’re willing to look beyond the Maksutov-Cassegrain optical design, the Sky-Watcher Virtuoso GTi 130p and 150P are ideal for both lunar, planetary, and deep-sky views while offering tabletop or tripod compatibility, wide fields, excellent optics, and very compact form factor alongside motorized GoTo/tracking. They can even be aimed manually to no ill effect on the GoTo system, which is controlled entirely via your smartphone or tablet.

Optical Specs & Performance

Consistently throughout the ETX-90’s existence, it has been a 90mm (3.5”) f/13.9 Maksutov-Cassegrain telescope with a resulting focal length of 1250mm. Maksutov-Cassegrain telescopes use a spherical primary mirror and a spherical meniscus corrector lens, concave on one side and convex on the other, which has an aluminized portion acting as the secondary mirror. Light enters through the corrector, bounces off the primary, then the secondary, and goes to the back of the tube through a hole in the primary. The ETX uses a built-in “flip mirror” which either redirects light out the side by 90 degrees or straight through a port at the back. Focus is adjusted by turning a knob at the back of the telescope to slide the primary mirror back and forth inside the tube.

The “folded” nature of the Maksutov-Cassegrain design is what gives the ETX-90 its super-long focal length despite its stubby tube. Maksutovs are easy to manufacture to high tolerances and there is little quality variation throughout all ETX-90 (as well as 105/125) models and units optically. All are essentially perfect optically and display the sharpest possible images for a telescope of this size. There is no difference between an ETX and a Questar at the eyepiece that you are going to notice, and the ETX will outperform a typical 3” refractor or 4” reflector on the Moon, planets, and double stars.

There are a few advantages to the ETX-90’s super-long f/14 focal ratio – focusing is easy thanks to the huge depth of field, even the cheapest eyepieces display images with tack-sharp stars right to the edges of the field of view, and you can achieve high magnifications without a crazy short focal length eyepiece or Barlow lens. A 90mm telescope with near-perfect optics like the ETX-90 can handle up to around 180x magnification, or a 7mm focal length eyepiece, before you run out of resolving power – though the best planetary views are usually found at a slightly lower power, around 100x. 

The tiny aperture and long focal length of the ETX-90 ruins any capability in viewing deep-sky objects. A 90mm telescope is terribly small for deep-sky viewing to begin with, but refractors and reflectors around this range with very short focal lengths and/or 2” focusers can achieve a wide field of view ideal for viewing the largest open star clusters and nebulae. The ETX-90’s 1250mm focal length and 1.25”-only eyepiece capability combined with physical stops inside the telescope’s baffle tube limit the maximum achievable field of view to just 1.25 degrees, or about 2.5 times the angular diameter of the full Moon, while the lowest magnifications you will be using are likely to be 40x or more – a typical ideal low power with a 90mm telescope would be more like 25x or even less. 

The ETX-90 completely lacks the ability to reveal detail in galaxies, resolve globular star clusters and planetary nebulae, or give you immersive views of the larger emission nebulae that dot the sky, even under perfect conditions. This is a telescope for the Moon, planets, and double stars. Look elsewhere if you want anything more than the most casual and low-quality of deep-sky views.

What Can You See With the Meade ETX-90?

The ETX-90 is an ideal telescope for viewing the Moon and planets. With the ETX-90, you can expect to see Mercury and Venus’ phases, details just a few miles/kilometers across on the Moon, Mars’ ice caps, Jupiter’s four large Galilean moons and cloud belts, Saturn’s rings and its brightest moon Titan, as well as Uranus and Neptune (which will appear as little blue dots). With some effort, you may be able to observe a few dark spots on Mars corresponding to dark patches of sand, which sometimes change in size or shape, the Great Red Spot on Jupiter, and the Galilean moons’ shadows when they are transiting the planet. It’s also possible to resolve Saturn’s cloud belts, the Cassini division in Saturn’s rings, and a few additional moons of Saturn, including Rhea. The ETX-90 is also great for splitting double stars as its sharp optics provide crisp Airy disks and it doesn’t suffer from chromatic aberration (as in a refractor) or diffraction spikes (which most reflectors have). Thousands of colorful double stars can be observed with the ETX-90 and the GoTo of most units will take you right to them.

Unfortunately, the ETX-90 does not perform very well when it comes to deep sky objects such as galaxies or globular clusters: at best, one can catch sight of Andromeda or M82 along with a dust lane or two, but this is only with some difficulty even under ideal conditions to the trained eye. You may struggle to see galaxies at all if you are under light-polluted conditions with the ETX-90’s tiny aperture. Open star clusters, too, are rather unimpressive due to the narrow field of view offered by this telescope. The Orion Nebula is of course a delight, but most other nebulae are lackluster – many large ones don’t fit in the field of view, and planetary nebulae are dim and unresolved. Globular star clusters require at least a 5” instrument to resolve into individual stars and remain faint fuzzy dots with the ETX-90. At the minimum, a 4-6” tabletop Dobsonian or a larger 8”, 10” or even 12” instrument is what we would recommend for enjoyable and detailed views of most deep-sky objects.

Meade ETX-90 Accessories

The ETX-90 has pretty much always come with a 26mm “Super Plossl” 1.25” eyepiece as a standard. This is almost always from the “Series 4000” line of “Super Plossl” eyepieces. While there is some slight variation depending on the date of manufacture, these eyepieces pretty much all feature a 52-degree apparent field of view, acceptable eye relief with glasses, and of course provide 48x with the ETX-90 translating to a true field of view of just over 1 degree, or about twice the angular diameter of the full Moon in the sky. The 26mm Super Plossl is acceptable and provides sharp views right to the edges of the field, though 52 degrees is hardly immersive.

You can squeeze a little more true field out of the ETX, either with a wider-field eyepiece or something with a longer focal length. A 32mm Plossl (39x) provides slightly brighter views of deep-sky objects and a wider field of 1.33 degrees, while a 40mm Plossl (31x) will be easier to look through and produce a brighter exit pupil than the 32mm but does not deliver a wider true field due to the limitations of the 1.25” barrel diameter, and its mere 40-degree or so apparent field of view can be a little claustrophobic. Both 32mm and 40mm eyepieces have sometimes been supplied with the ETX-90.

The most commonly supplied ocular, besides the 26mm Super Plossl bundled with the ETX-90, is a 9.7mm Super Plossl (129x). While sharp and delivering an ideal magnification for lunar, planetary, and double star viewing, the Plossl design tends to be uncomfortable to look through at focal lengths of below 13mm or so, requiring you to jam your eye into the lens to see anything – particularly problematic if you have long eyelashes, need to wear glasses due to astigmatism in your eyes, or do a lot of observing with the general public or children who may have trouble looking through it. As such, it may warrant replacement.

Other eyepieces sometimes supplied with the ETX-90 include a 15mm Super Plossl (83x) which is pretty good, a 20mm (63x) which is somewhat redundant but works fine, a 12.4mm (101x) which is somewhat uncomfortable to look through but certainly better than the 9.7mm, and disastrous 6.4mm (195x) and 5mm (250x) Super Plossls, both of which are nigh-impossible to look through and easily exceed the magnification the ETX-90 can ever handle (180x is already a little too much). A 2x “Shorty” Barlow lens is sometimes supplied with the ETX-90, and it works okay when used in conjunction with a Plossl or other eyepiece to get higher magnification, but can add some chromatic aberration and other distortion to the view – short-barrel Barlows use stronger lenses which tend to cause more optical problems – and it’s generally inferior to a fixed shorter focal length eyepiece. A 3x “Shorty” Barlow is also offered which is usually poor quality and produces too much magnification to be useful with most eyepieces. 

Occasionally, you may also see an 18mm “WA” wide-angle eyepiece (69x) with a roughly 60-degree apparent field of view, translating to only a slightly narrower true field than the 26mm Plossl. Even more seldom are the Series 4000 SWA and UWA eyepieces, variants on the Erfle and Nagler Type 1 designs, respectively. The 4.7mm UWA is not the most comfortable to look through and produces too much power for the ETX-90 anyway; the 6.7mm is a great high-power eyepiece at the limit of the scope’s capabilities while the 8.8mm and 14mm are excellent but unlikely to come with an ETX-90. The 13.8mm, 18mm, and 24.5mm SWA eyepieces are superb in the ETX-90 and highly recommended.

If your ETX-90 did not come with a set of good eyepieces, we would recommend a good 32mm Plossl (32x), 9mm (139x) “gold-line” or “red-line” eyepiece and some sort of ocular in the 14-16mm range with a wide apparent field of view such as an SWA, UWA, goldline or redline design. There is no need to worry about brand, premium tier kit, or really even getting more than two or three oculars; a huge set of fancy eyepieces is simply overkill for this telescope.

For a finder, the ETX-90 can come with one of four designs. Earlier versions used an 8×21 erect image, straight-through finder. This finder is mounted too close to the tube, it can only be used with your right eye and is often completely inaccessible when the telescope is aimed high in the sky. The view is extremely dim due to the use of an erecting prism and the rather high 8x magnification coupled to the finder’s teeny aperture. It is also very hard to adjust the focus or align the 8×21 finder accurately. An upgraded 8×25 right-angle finder, meant for the ETX-105 and 125, is sometimes seen with the ETX-90 and works pretty well, with adjustable focus and a much brighter view. The LNT finder and red dot finder on newer ETX-90 models work great and are more than adequate to aim the telescope, though usually only needed to align the AutoStar/AudioStar GoTo system on the sky.

Tripods

The Meade ETX-90 has been historically supplied with three tripods: the tabletop legs, the #883 tripod, and the #884 tripod. The scope also fits any standard photographic or surveyor tripod with a ¼ 20 stud that’s sufficiently sturdy if need be, and adapters for fitting the larger Meade Standard Field Tripod exist as well.

The #881 tabletop legs for the ETX-90 really are only needed for the RA or EC versions which must be used in an equatorial configuration to track. Other versions of the ETX-90 can rest flat on a table. Either configuration is fairly sturdy, but you must be careful not to disturb the scope, which can ruin alignment. You can find the tabletop legs for under $30 USD on sites like eBay.

The #883 tripod is a simple extruded aluminum tripod with a plate on top, requiring attachment of the ETX-90 with two hand knobs (which are far, far too easy to lose by accident). There are fine adjustments in both altitude and azimuth to use the scope in an equatorial configuration if you have the RA or EC, though it is a little unsteady if you do so. It is similarly inadequate for holding the larger ETX models. However, for the AutoStar and AudioStar-equipped ETX-90 units, it works fine. The smaller #882 tripod should be avoided and is usually only seen with the small ETX refractors. The #883 tripod is usually worth about $30-$70 USD.

The #884 tripod is a beefy steel tripod that holds any of the ETX models with ease. It has a built-in equatorial wedge, which is steadier than the #883 but lacks fine adjustments – however, for most users, this is not a problem if you just want motorized tracking with the RA or EC models. Some #884s come with a metal accessory tray, while others have a plastic one. The #884 has captive knobs for attaching your ETX-90 at the top of the tilt plate. You can usually find a #884 tripod for $80-$140 USD; don’t pay more.

Meade ETX-90 Versions

Original ETX-90 “RA” – 8/10 stars

Pros:

• Usually available for very little money
• Simple RA drive is unlikely to fail and quick to set up
• Lighter than most other ETX-90 options
• Usually still in good shape after nearly three decades

Cons:

• Low-quality finderscope is nearly unusable
• Lots of fragile hardware holding mount together
• Tiny adjustments for manual aim
• Motor drive has severe backlash and often lags

The ETX-90 was introduced in 1996 and originally just marketed as the “ETX” – the 125mm and 105mm Maksutov-Cassegrain versions, along with the small low-quality refractors, came later. The RA designation is a retroactive label referring to the simple clock drive in the telescope, which drives it to track the sky in right ascension by tilting it with one axis aimed towards Polaris or the South Celestial Pole, converting it into an equatorial mount. The clock drive runs on a set of AA batteries, and you manually aim the scope around the sky by unlocking a pair of clutches and then using tiny slow-motion adjustments to fine-tune your aim. Once the RA clutch is engaged, the drive kicks in – at least in theory.

The ETX-90 RA’s clock drive is simple to set up, but you need to tilt the whole telescope on its fork mount to polar align it as an equatorial fork configuration. This requires either an equatorial wedge, using the tilt plate on an #883 or #884 tripod, tilting a photo tripod head and putting the ETX on top, or using the scope with the little tabletop legs often supplied with the RA or easily found on eBay. In the equatorial configuration, you may be unable to aim the telescope near the horizon without it hitting the mount, or anywhere between the zenith (straight up) and north celestial pole due to the awkward angles the finder and eyepiece will be placed at.

The clock drive of the ETX-90 RA is nice in theory, but frequently fails – either literally or figuratively. Given that the newest ETX-90 RAs were made around the year 2000, even the simple electronics are often failing (contrary to the well-made stuff in more expensive Meade, Celestron, and other mounts decades older which usually still runs without a hitch, the circuits and solders in the ETX-90 RA are hardly able to withstand the test of time). Additionally, there is a severe lag between when you lock the RA clutch/turn the drive on and when it actually kicks in – at high power, your target may have drifted across the entire field of view before the drive bothers to do its job. 

Furthermore, the all-plastic fork mount of the ETX-90 RA extends to its declination axis clutch lock, which uses a metal knob but a plastic clamp. This part can frequently break and it is very hard to get smooth manual motions even with the best possible combination of lubricants. The slow-motion knobs on both the RA and declination axis are similarly full of slop/backlash even when fine-tuned by the careful user.

As a result of the RA mount’s issues and fragility, many optical tubes today are separated from their fork mounts. The problem is that this can frequently result in the scope being much heavier or costly to properly mount than is worthwhile to deal with, especially if the new mount in question puts the eyepiece at an awkward angle.

If you are lucky and can find one still mated to a working fork, with some care, the ETX-90 RA can be a fabulous little scope. The author has had several. Yes, the RA may have its quirks, but learning to deal with them enables you to take advantage of nearly unmatched convenience compared to the bulkier and time-consuming gizmo-laden AutoStar and AudioStar versions.

Expect to pay between $80-$180 USD for an ETX-90 RA, plus the cost of a suitable tripod – usually under $275 USD for a full package.

ETX-90 EC/AT – 7.5/10 stars

Pros:

• Extremely common
• GoTo capability at least an option
• Push-button aiming solves physical ergonomic constraints of tiny adjustments
• EC version can still be aimed manually

Cons:

• Still has the horrible finder scope of the RA
• Inaccurate GoTos and often severe backlash in motors
• EC 492 hand paddle is confusing to set up and use
• Secondary mirror baffle can sometimes randomly fall off or slide

After the success of their first GoTo telescopes, the LX200, Meade was looking to do something new to do with GoTo and rolled out the AutoStar system, integrating it into the ETX. The AutoStar system provides full motorized tracking and GoTo capabilities with the ETX-90 and was eventually added to Meade’s higher-end telescopes too, as well as new ETX models. The interface is extremely clunky, however, requiring you to set the date, time, and location as well as acknowledging a half dozen prompts before even choosing the alignment process. The clutches on the AT/EC ETX-90 are still there but the manual fine adjustments are gone. You cannot unlock the clutches and manually aim any ETX version with GoTo without ruining the alignment of the AutoStar on the sky. The AutoStar works okay if you don’t mind the interface, though the gears in the ETX-90 can have lots of backlash, are loud, and, being plastic, tend to strip and break over time. The ETX-90 EC and AT also still have the godawful 8×21 finder of the original ETX-90 RA and may or may not come with a tripod by default.

The ETX-90 EC is merely a stripped-down AT unit, sold as a “budget” option to cut costs, though most AT units will say “EC” on the box and come with the AutoStar #497 controller in a separate package. The EC unit features a simple #492 hand paddle with adjustable speed rates and arrow keys to move the scope. By adjusting an internal screw you can set it to automatically track on the azimuth/right ascension axis, provided the scope is of course appropriately tilted to be aligned with the celestial pole. It works okay but the backlash in the motors can be annoying. You can upgrade any ETX-90 EC to an AT version with a #497 Autostar, or get a #495 and re-flash the software to convert it to a #497. The AudioStar controller will also work with the ETX-90 EC. However, a #494 or #493 controller will not work and you wouldn’t want to use one anyway.

Defects with older ETX-90 AT and EC versions are common, such as cable, controller, or drive failure as well as mechanical damage to the gear and other parts. The most severe issue is that the glue holding the baffle around the secondary mirror of these telescopes can fail, and the baffle will slowly slide across the corrector (or simply fall off and bounce around inside the tube). Taking off the front corrector lens, removing the old adhesive, and re-gluing the baffle with silicone RTV is actually fairly easy to do but can be a stressful and delicate process.

A used ETX-90 EC is usually worth around $120-$220 USD, with the AutoStar #497 controller adding another $60-$80 onto the price. You are likely to find one bundled with an #883 tripod too. A 105 goes for $200-$350, while a 125 is usually $350-$500.

ETX-90 Premier Edition – 9/10 stars

Pros:

• More robust mount hardware
• UHTC coatings improve light-gathering ability a little bit
• Improved LNT technology, finder scope, Autostar makes aiming a lot easier and speeds up setup
• Better red dot finder

Cons:

• Hard to find for a reasonable price
• LNT window is easily broken or damaged
• LNT can fail
• Silk-screened tube art can look kind of ugly

The ETX-90 Premier Edition (PE) for short) has a variety of improvements over the older ETX-90 models. Gone is the complicated 3-star alignment of the regular AutoStar. Instead, you simply level the scope, point it north, and turn it on – after which the telescope automatically determines north and level using built-in gyroscopes, clocks, and a compass, and will slew to a single star for you to confirm alignment. A red dot finder is also provided for aiming, the internal gears are improved, the #884 tripod is standard, and things like the secondary mirror baffle falling off or parts of the mount breaking are not really a concern anymore.

The Premier Edition ETX-90 also sports a colorful nebula image on the optical tube (at least on most units) and UHTC coatings, which slightly improve light-gathering ability and reduce glare/internal reflections (albeit by only a few percent, simply not enough to notice).

The ETX-90 PE was discontinued due to the events of 2007/2008, where the financial crisis coincided with issues with Meade’s higher-end product lines leading to the near-total demise of the company. Its replacements, the cheapened “portable observatory” and “Observer” models, do not hold a candle to the PE. 

Downsides? Well, good luck finding one, or at least a good-condition unit at a reasonable price. Most PE owners hold onto their scopes, and used units are often laughably overpriced – on par with a new telescope of similar capabilities, if not higher. The fancy packaging and livery of the ETX PE telescopes seem to also induce know-nothing sellers on sites like eBay or Facebook Marketplace into thinking it is worth some outrageous sum more frequently too. It should be noted that the ETX-125 PE contains outright metal internals and usually isn’t much more expensive on the used market, while still a fairly convenient and portable instrument with much greater capabilities – consider the 125 if you are in the market for a PE model ETX telescope.

A used ETX-90 PE should be no more than $400 USD with a #884 tripod included, but $300 is a more reasonable price. The 125 PE is worth around $400-$600.

ETX-90  “Portable Observatory” – 8/10 stars

Pros:

• Red dot finder makes alignment easy
• Solid mount/tripod
• Improved AutoStar
• Most improvements of the PE are retained

Cons:

• Not very common
• Lack of LNT technology means alignment can be rather time-consuming
• AudioStar interface is still ancient and kind of a gimmick
• Not as well-supported by user community

The “Portable Observatory” ETX-90 model is essentially a stripped-down PE. Gone is the fancy LNT technology or nebula livery, though you still get a red dot finder and the #884 tripod. The Portable Observatory ETX-90 retains its predecessor’s UHTC coatings, not that that means much, but without the LNT technology, there’s little draw besides the reliability and comfort improvements compared to the old EC/AT units. 

ETX-90  “Observer” – 8.5/10 stars

Pros:

• Optical tube is easily attached
• Retains the good parts of many prior ETX-90 improvements
• Built-in Barlow lens like a Questar
• Improved ergonomics

Cons:

• More complex electronics = more to go wrong
• Much fatter and bulkier than prior ETX-90 models
• Dumb plastic spreader tray
• A decidedly outdated telescope considering it was made in the late 2010s

The ETX-90 Observer is similar to the Portable Observatory model but with a few additions. The finder attaches with a standard Synta/Vixen-style shoe to the tube, and the optical tube can also be removed from the mount to attach it to another mount if you wish, while the forks can hold some other small telescopes, provided they clear the base. The focus knob on the Observer is also bigger and easier to grab, while a 2x Barlow lens is built in and can be activated at the flip of a switch. You also get the AudioStar controller, which is identical to the AutoStar apart from being able to pointlessly spout out facts about whatever you’re observing (but retaining the ancient alarm-clock-like display, which is uncomfortable to look at). The ETX-90 Observer can also be controlled over WiFi with a suitable adapter dongle.

The ETX-90 Observer is decent, but compared to other newer telescopes, it feels outdated and incapable, while also being heavier and bulkier than most other ETX-90 incarnations. Expect to pay $250-$350 USD for a good used unit with a tripod and accessories.