Meade LX90 ACF Telescope: An Honest Review About Value

The Meade 8” LX90 ACF is one of several flagship telescopes from Meade’s lineup. The lightweight LX90 fork mount can trace its origins all the way back to the late 1970s when Meade started selling their 2080 8” Schmidt-Cassegrain. The 8” LX90 ACF shares a lot with those original scopes but of course features full GoTo rather than a simple wedge and clock drive as well as slightly better ACF optics and multi-coatings. Despite Meade’s multiple bankruptcies, buyouts, and product reshuffling, the 8” LX90 ACF has stayed the same since around 2008, and the LX90 EMC (identical apart from the older AutoStar controller and lack of the ACF optical configuration) has been around since the early 2000s. 

The Meade LX90 can be best thought of as a stripped-down LX200, with many of the same features for observers in a trimmed, lightweight, and more affordable package but with far fewer astrophotography capabilities. However, compared to other options at this price range, namely from Celestron, the 8” LX90 ACF faces fierce competition to the point that it probably isn’t worth buying unless no alternative 8” Schmidt-Cassegrain configuration is available to you. For sheer bang for your buck, other telescope types and configurations are likely to prove superior for astrophotography use or visual observation. However, the 8” LX90 ACF isn’t bad – just a little expensive and lacking in versatility for what it is.

8.5/10 stars

Pros

• Great optics
• Fairly portable
• Some astrophotography capabilities
• Tracking/GoTo works well

Cons

• Long focal length limits maximum field of view
• AudioStar interface is rather outdated
• Tube is permanently attached to fork mount
• Expensive for what you get

How the 8” LX90 ACF Compares to Other Products

• Celestron NexStar Evolution 8 – The NexStar Evolution 8 features a considerably more advanced mount than the 8” LX90 ACF, with features like a built-in lithium battery and WiFi operability. The EdgeHD/StarSense version has even better flat-field correction for astrophotography than the Meade ACF optics while the StarSense AutoAlign further speeds up getting ready for a night of viewing.
• Celestron CPC 1100 GPS – The CPC 1100’s huge 11” primary mirror blows away a smaller telescope like the 8” LX90 ACF on all targets while the rock-solid and easy to use fork mount and tripod provide an ideal platform for this telescope. However, the CPC 1100 is rather bulky and heavy, with a permanently integrated tube/mount assembly like the LX90 ACF scopes.
• Celestron Advanced VX 9.25″ Schmidt-Cassegrain GoTo – The Advanced VX mount enables deep-sky astrophotography capabilities with a smaller telescope while the Celestron C9.25 XLT optical tube easily detaches from the mount when not in use, and offers slightly more light-gathering and resolving power than an 8” Schmidt-Cassegrain.
• Celestron CPC 800 GPS SCT GoTo – The CPC 800 GPS is compatible with a wider range of accessories than the 8” LX90 ACF, the NexStar+ controller is easier to use, and the CPC 800 is also sold at a lower price most of the time, as well as featuring a sturdier mount/tripod.
• Meade 8” LX200 ACF – The 8” LX200 ACF’s improved hardware and software make it significantly better for astrophotography than the LX90 and the various Celestron fork-mounted 8” SCT configurations, but it is needlessly bulky for visual use and superior equatorial mounts are less expensive and more capable to purchase for holding one of these telescopes.

Optical Tube Assembly

The Meade 8” LX90 ACF is an 8” (203mm) f/10 Schmidt-Cassegrain telescope (SCT) with a focal length of 2032mm. This is identical in specs to the Celestron C8 XLT telescope optical tube, which is of the same design and pretty much identical in physical size and performance. The 8” LX90 ACF utilizes a spherical f/2 primary mirror and a convex aspheric secondary mirror for optimal light focusing within the short tube. The Schmidt corrector at the front eliminates severe spherical aberration caused by the primary mirror. The ACF design uses slight tweaks to the curvature of the mirrors to reduce issues like field curvature and coma at the edges of the field of view, which you’re unlikely to notice visually but can be an issue for deep-sky astrophotography. However, it’s inferior to the Celestron EdgeHD design, which adds corrector lenses for an even flatter field alongside other features like mirror locks and cooling vents.

When collimated, the 8” LX90 ACF offers great views of the Moon, planets, and many smaller deep-sky objects – the long 2032mm focal length limits your field of view even with a 2” eyepiece or f/6.3 focal reducer. Collimation is adjusted with three small screws at the front of the telescope, while focusing occurs via a knob at the back of the scope, moving the primary mirror along a rod inside the optical tube, which changes both the spacing between mirrors and focal plane location. “Image shift” – where the view appears to bounce or rock around independently of any vibrations – can occur while focusing due to play or wobble as you turn the knob and move the mirror, while mirror flop is caused by long-term sagging of the focusing rod; both occurrences can ruin longer exposure astrophotos. Meade’s more expensive scopes and the Celestron EdgeHD design have mirror locks which prevent mirror flop during long-exposure astro-imaging, but the LX90 ACF line does not.

The 8” LX90 ACF is compatible with various Schmidt-Cassegrain threaded accessories which attach to the back of its rear port, including the provided 1.25” visual back, an f/6.3 focal reducer, screw-on star diagonals or a camera T-adapter. A 2” star diagonal and eyepieces, or f/6.3 focal reducer, is highly recommended to achieve the maximum possible low-power field of view with this scope for deep-sky viewing, while a focal reducer is also a good idea for deep-sky astrophotography.

The Mount

The 8” LX90 features a GoTo alt-azimuth fork mount with adjustable clutches. Theoretically, you can manually aim the telescope with the clutches unlocked, but without any sort of slow-motion gearing or other hand-powered fine-tuning adjustment there is little utility in doing so. Attempting to adjust the scope manually while it’s powered on will ruin the accuracy of any GoTo or tracking if you try to do it while the mount is powered on and aligned. The 8” ACF optical tube is permanently attached to the LX90 fork mount, and has to be removed via several screws (as well as bolted to a dovetail plate) if you want to switch it out for another mount.

Assembling the 8” LX90 ACF for a night of stargazing is quite easy; just extend the tripod, attach the spreader tray, and secure the scope with three screws. The scope can then be powered on and aligned, with various options including one, two, and three-star alignment (more alignment points leads to better accuracy). The LX90 mount’s GPS unit does save some time by auto-updating time/date/location information but otherwise isn’t especially useful for aligning or using the telescope. It can fail and nothing of consequence will be lost besides a minor inconvenience when setting up. 

The 8” LX90 ACF is operated with the provided Meade AudioStar controller, which has a red LED display similar to an alarm clock as well as a speaker, allowing it to output audio information about what the telescope is currently pointed at or doing. While the interface is a little outdated, the bigger issue is that you have to acknowledge or even sit through several prompts just to get started with using the telescope. You can also control the scope directly via a PC with a serial port adapter, or purchase a WiFi adapter and operate the 8” LX90 ACF with an app such as SkySafari. The mount can run off a set of 8 C batteries stored inside the base or you can get a rechargeable external power supply, which is far more economical if you use the scope frequently. Keeping C batteries inside the telescope as a backup in case your power fails or accidentally is disconnected would be a good idea to avoid having to re-align the scope or have your night come to a premature ending altogether.

While we wouldn’t recommend air travel with it, the 8” LX90 ACF tube/fork mount combination is compact enough to fit in a suitcase or rolling tool tote with room left for the controller, tripod spreader and other accessories, which can make storage and transport really convenient.

The Scope’s Accessories

The 8” LX90 ACF comes with a basic set of accessories; as with most telescopes at this price range, it’s assumed you will go and get an additional kit or already have some. The provided accessory set includes a 9×50 finderscope, 1.25” visual back, 1.25” prism star diagonal and a 1.25” 26mm Plossl eyepiece that provides 78x magnification with the telescope. While 1.25” accessories come standard, opting for a 2” diagonal or an f/6.3 focal reducer will give you an even wider field of view than is possible with just 1.25″ eyepieces at f/10. The included 9×50 finder offers a 6° field of view (upside down) with crosshairs to see stars or bright deep sky objects faint enough to not be visible to the naked eye – this may be overkill for some GoTo telescopes but it’s still nice to have! The finder attaches with a standard Meade/Explore Scientific type shoe, so you’ll need to get a Synta/Vixen-style base plate for attaching many other finder scopes.

What Can You See With the Meade LX90

Even when viewing from light-polluted cities and suburbs, the 8” LX90 ACF provides plenty of fascinating views of the night sky. With its stock 1.25” diagonal and eyepiece, some larger open star clusters won’t fit in the scope’s field of view, but those that do make for breathtaking sights. Examples include the Double Cluster in Cassiopeia, the Wild Ducks (M11) in Scutum, and the Pleiades (M45) in Taurus. 

Bright globular star clusters like M13 will be visible under all but the worst sky conditions, while thousands of double stars can also be split with this telescope. Even the brighter emission nebulae such as Orion (M42) or the Lagoon (M8) are still partially visible from light-polluted locations – albeit less vibrant than their appearance under dark skies. A UHC nebula filter enhances these objects, and under dark skies, a good filter will also bring out additional nebulae which are otherwise too faint to see even against the natural sky background. Colorful planetary nebulae like the Ghost of Jupiter or the Cat’s Eye also stand out under even fairly bright skies and reveal fine detail when the air is steady, though locating them at low power can be difficult as they appear as nearly star-like points, requiring a careful eye or UHC filter to bring them out.

Under dark skies and ideal observing conditions, the 8” LX90 ACF does a superb job on deep-sky objects as is to be expected of any good 8” telescope. Galaxies, which remain unresolved smudges under brightly-lit suburban skies, explode into detail under dark skies. Objects such as M64 and M82 stand out with their visible dust lanes, and hints of M51’s spiral arms can be seen on the best nights. The Virgo Cluster of galaxies can show dozens or even hundreds of individual members. The two companion galaxies orbiting Andromeda (M32 and M110) appear as fuzzy spots next to its striking dust lanes, which reach far beyond the telescope’s maximum achievable field of view at low magnification.

The 8” LX90 ACF is also ideal for viewing Solar System objects. You can easily make out the phases of Mercury and Venus, as well as dust storms and the polar ice caps on Mars. Mars reveals additional detail in the form of dark markings on its surface when the planet reaches its closest approach to Earth biannually. 

Jupiter’s various atmospheric features, such as its main equatorial cloud belts, festoons, storms, and the Great Red Spot are clearly visible in the 8” LX90 ACF along with its four large moons, the Galilean moons Io, Europa, Ganymede, and Callisto. On a steady night, all four moons appear as tiny disks, which are particularly evident when they frequently transit in front of the gas giant and cast shadows behind them. Saturn’s rings display in all their glory, including the Cassini Division within them. Some cloud belts on Saturn itself and a few of its moons can be seen with the 8” LX90 ACF, though they appear only as star-like pinpoints of light. 

Uranus’ disk is resolved while at least one or two of its four largest moons can show up under dark skies in the 8” LX90 ACF; however you will likely need a larger instrument. Neptune appears as a star-like point though its moon Triton is fairly conspicuous next to it, while distant and faint Pluto is technically visible with an 8” instrument but in practice requires a larger telescope to pick out for all but the most seasoned observers under ideal conditions.

Astrophotography Capabilities

As an alt-azimuth mounted design, in its stock configuration, the 8” LX90 ACF is only good for visual observation and planetary astrophotography. Converting the telescope to an equatorial mount can be done by purchasing or making a wedge to tilt the telescope’s axes to align with the celestial equator and poles, precisely polar aligning, and then booting the mount into an equatorial configuration. However, the 8” LX90 ACF’s mount uses cheap DC servo motors and lacks a direct autoguider port connection. Controlling and guiding the mount through a PC will require the use of a serial adapter and various other cables which is a huge pain, and the DC servos limit tracking/guiding accuracy anyways. The lightweight and spindly fork mount of the LX90 is also not ideal for an astrophotography setup, particularly with the additional load of a camera, autoguiding setup, etc. And of course, polar aligning a fork-mounted telescope on a wedge is a pain, especially when the telescope lacks the software to help you out, as is the case with the LX90.

While workable results can be obtained, we generally wouldn’t recommend deep-sky astrophotography with the 8” LX90 ACF, or any fork-mounted telescope. A German equatorial mount is more versatile, provides better tracking/guiding accuracy, and can be used with a smaller telescope to start out with, as an 8” Schmidt-Cassegrain is unwieldy, expensive, and has extremely stringent requirements for tracking accuracy, which can frustrate beginners with blurry images.

Planetary astrophotography won’t require much investment and is not nearly as demanding of tracking accuracy, equipment, or your time with the 8” LX90 ACF. Just pop in a good 2x or 3x Barlow lens and a suitable planetary camera like the ZWO ASI224MC, plug the camera into your computer and you’re ready to go. Decent captures of just a few minutes are all it takes for stunning images of the Moon, planets, or even the Sun if you put a safe white-light solar filter on the front of the telescope. The alt-azimuth mount design and cheap servo motors are not at all limiting when it comes to taking these short video exposures, and any video image stacking software will compensate for any drift of your target across the frame.

Final Thoughts

The biggest issue with the 8” LX90 ACF is its cost. The 8” LX90 ACF costs nearly $1,000 USD more than the Celestron NexStar Evolution 8, a telescope with equal optics, slightly more provided accessories, and features the 8” LX90 ACF lacks like worm gears, a detachable tube, and built-in WiFi and lithium batteries by default. You could get the deluxe EdgeHD/StarSense-equipped Evolution 8 or even a bigger Schmidt-Cassegrain telescope from Celestron for the same price as the 8” LX90 with more capabilities and features. Meanwhile, an 8” Dobsonian costs a fraction as much and puts up the same views while a larger one will blow away the 8” LX90, and better setups for astrophotography exist.

If you don’t mind the price or can get a good deal, the Meade 8” LX90 ACF is a good telescope, though some aspects such as the hand controller interface do come across as a little clunky and outdated.