The 8″ SCT Optical Tube Performance
The Meade 8” LX200 ACF is an aplanatic Schmidt-Cassegrain telescope (SCT) that features an 8” (203mm) aperture and a focal length of 2032mm.
It uses a spherical f/2 primary mirror and an aspheric secondary mirror, which “folds” the image path into its stubby tube, directing light out the back through a hole in the primary mirror, while its Schmidt corrector removes spherical aberration. The ACF design’s use of a highly aspheric secondary mirror reduces the coma and field curvature seen in a normal Schmidt-Cassegrain, but not as well as the Celestron EdgeHD design, which uses corrector lenses.
Unlike the Celestron C8 XLT, the Meade 8” ACF’s oversized primary mirror and baffle tubes mean that I don’t get vignetting issues when I use a 2” eyepiece or medium-sized camera sensors. The Celestron 8” EdgeHD did not have this problem either.
The 8″ LX200 ACF provides me great views of the Moon, planets, and many small deep-sky objects when it is properly collimated on account of its 8” aperture. The 8” LX200 ACF has three small screws at the front of its secondary mirror holder for adjusting collimation. More information on how to collimate Schmidt-Cassegrain telescopes can be found in our collimation guide.
However, as is typical for an 8” Schmidt-Cassegrain, the scope’s long 2032mm focal length restricts my field of view to about 1.3 degrees across, or about 2.5 times the angular size of the full Moon, even when I use a wide-angle 2” eyepiece or an f/6.3 focal reducer. This isn’t as wide as the field of view offered by 8” or 10” Dobsonians (which can reach over 2 degrees) and prevents me from fitting the largest deep-sky objects in the field of view.
The Focusing & The Issues
As with most Schmidt-Cassegrain telescopes, the 8” LX200 ACF has a threaded port at the back for attaching accessories and a knob that acts as its focuser. This knob at the rear of the optical tube moves the primary mirror, adjusting the spacing between the primary and secondary mirrors and thus moving the focal plane location for different accessories, cameras, etc. The diagonal/eyepiece or camera adapter attaches to the back of the telescope with standard SCT threads and remains static when focusing is adjusted.
As with all Schmidt-Cassegrain telescopes or other instruments with a moving-mirror focuser, there is a potential issue of “image shift,” where the wobble of the focusing rod when turning the focus knob causes views to appear to bounce around. But this was relatively minimal with the 8” LX200 ACF when I tried one.
The issue of “mirror flop”, where long-exposure astrophotos tend to become out-of-focus as the mirror shifts on the focusing rod, is solved by a mirror locking knob, which you can tighten after focus is achieved with your camera.
The Accessories
The 8” LX200 ACF includes Meade’s standard basic accessory set for their ACF Schmidt-Cassegrain telescopes.
We get a 1.25” prism star diagonal, a 1.25” visual back to attach it to the telescope, and a single 1.25” eyepiece—a 26mm Plossl yielding 78x magnification with the 8” ACF optical tube.
The eyepiece, as I experienced, is decent, if basic, with a 52° apparent field of view, translating to a true field of almost exactly ⅔ of a degree with the 8” ACF.
The finder scope Meade provides with most of their ACF telescopes is a 9×50 straight-through unit with crosshairs and an upside-down field of view.
I can focus this finder by twisting the eyepiece, which I found to be a nice bonus. The field of view is 6°, which is plenty wide, and the finder shows stars a few magnitudes fainter than what my eye alone can show thanks to its 50mm aperture. I see it as an overkill for aligning a GoTo telescope but it works just fine for the job.
The Meade/Explore Scientific finder shoe attached to the 8” ACF optical tube does allow me to interchange the provided 9×50 unit with other finders via a compatible adapter or bracket if I want to.
The Altitude-Azimuth Fork Mount
The 8” LX200 uses an alt-azimuth GoTo fork mount. The telescope is more or less permanently attached to the mount. Removing it is a time-consuming and tedious procedure that I’d only do once, if at all—to put a dovetail on the optical tube and ditch the fork.
The LX200, much like the LX90, runs on servo motors, which I find inferior to steppers for astrophotography due to their lack of precision, not to mention their noisy operation. However, for visual work and other less-demanding applications like planetary imaging, it does the job. I can autoguide the mount if I use it on top of a wedge to convert it to an equatorial fork.
The mount has clutches and azimuth/RA slow-motion adjustments for manual aiming, but these ruin my GoTo alignment if I use these when the scope is powered up. Also, manually aiming the LX200 in altitude/declination is not really possible due to the lack of fine adjustments on that axis.
The setting circles on the mount are similarly little more than a useless decoration lacking the precision to be a working tool of any sort.
The LX200 mount is a little beefier than the LX90 design, reducing vibrations somewhat at the cost of increased weight. The 8” LX200 ACF clocks in at 45 lbs vs. the 33 lbs 8” LX90 tube/fork package, though both telescopes use Meade’s Standard Field Tripod, weighing in at 19 lbs. The 45-pound LX200 fork/OTA assembly is heavier than any 8” or 10” Dobsonian optical tube I’ve had my hands on and is similar in weight to that of a solid-tubed 12” Dob. The total 64 lb. assembled weight is on par with a 10” Dobsonian.
And if you think it’s less awkward due to the stubbier profile, think again.
A Dobsonian tube just has to be roughly set on its mount. The 8” LX200 needs to be delicately maneuvered to at least line up a hole in the center of the fork mount assembly with a center post on the tripod. I’ve witnessed many users purchasing a Starizona Landing Pad or similar aftermarket/DIY tool to help with this process.
Assembly of the 8” LX200 ACF consists of assembling/leveling the tripod and accessory tray and then putting the scope/forks atop, then powering up for alignment. You can run the scope off eight C batteries but I opted for a DC/AC power supply as it is a more economical and convenient option, though keeping batteries in the compartment works as a failsafe in the event external power is briefly lost, avoiding a need to align the scope again and start all over.
AudioStar Hand Controller & The GPS Unit
The 8” LX200 ACF’s provided AudioStar hand controller has a variety of alignment possibilities, but generally, I believe 2 or 3-star alignments are the most accurate and straightforward for a night of observation. The quick align and auto align features often suffer from lack of pointing/tracking accuracy over long periods or between multiple objects.
The provided Meade AudioStar controller, is basically an updated Autostar controller. Like the Autostar, which itself dates back to the 1990s, the AudioStar features an unappealing red LED display. Its selling point is more of a gimmick in that it can relay auditory information about what the scope is pointing to or doing. I don’t really see much benefit to this, and the interface just feel slow, uncomfortable, and outdated compared to a Celestron or Sky-Watcher controller.
Thankfully, it is possible to install an aftermarket WiFi adapter to control the scope over SkySafari Pro or Stellarium smartphone apps, or just plug the scope into our PC with the correct serial port adapter cables.
Like the AudioStar controller, the GPS unit in the 8” LX200 ACF is barely more than a gimmick. It saves us a few seconds of effort setting up the telescope by entering in the location, time, and date information, but a WiFi adapter can just get that information from our phone (and we can just pull up that information anyhow regardless).
In addition to adding to the cost, the GPS unit sometimes failed to sync or simply stop working entirely, though it didn’t affect the operation when it failed.
I can recall that Meade and Celestron used to trumpet this feature with their respective GPS telescopes a lot more than nowadays as if the GPS was some sort of way to help the telescope navigate the night sky. Thankfully, it is now more of a footnote.
Should I buy a Used Meade 8” LX200 ACF?
There is about as much of a point in buying a used 8” LX200 as there is a new one. These telescopes are just cumbersome for what they provide.
Older LX200s are often sold for outrageous prices as many people seem to think little has changed between versions or simply that these telescopes retain value better than they actually do.
Pre-2007 LX200 telescopes will lack the ACF optics; early ACFs are labeled “LX200R” due to some nomenclature/marketing terminology Meade was using at the time. The pre-ACF LX200 telescopes (including the LX200R) use an AutoStar controller in lieu of the AudioStar, while the first LX200 or “Classic” telescopes use a very antiquated hand controller. You won’t notice much difference in typical use between an old LX200GPS, LX200R, and the current ACF versions.
The LX200 Classic telescopes are unable to accept an AutoStar or AudioStar handset and use tantalum capacitors which are prone to shorting themselves; these telescopes are severely limited by the technology of their time even if they still work (being over 25 years old) and should probably be avoided.
As with any used Schmidt-Cassegrain telescope, make sure that the corrector coatings on the 8” LX200 are free of damage and that the mirrors are not corroded. A cracked corrector or one with coating “fog” cannot be repaired economically. The electronics should also be tested before purchasing if possible.
Alternative Recommendations
Normally we categorize our alternative recommendations by price range, but with such a wide selection (combined with the 8” LX200’s sky-high price) we’ve elected to give you some simpler guidance instead.
Dobsonians
- The Sky-Watcher Flextube GoTo Collapsible Dobsonians are available in 8”, 10”, 12”, 14”, and 16” apertures as well as manual-only formats for the smaller three. These telescopes are compact and the GoTo functionality seamlessly allows manual aiming thanks to the Sky-Watcher FreedomFind encoders, while the simple FlexTube design increases portability without adding too much complexity for setup.
- The Apertura AD Dobsonians are available in 8”, 10”, and 12” apertures. These telescopes provide some of the best “bang for your buck” of any telescope sold today and offer fantastic views at the eyepiece, sturdy mounts, and a decent bundle of provided features and accessories.
- The Explore Scientific Truss Tube Dobsonians – available in “hybrid” and deluxe 10” as well as 12” and 16” apertures – are all-metal Dobsonian telescopes with buttery-smooth mounts, extremely compact designs when dismantled and of course excellent optical performance. However, they include little in the way of useful accessories and a truss tube scope is of course more complex to assemble in the field.
- The Celestron StarSense Explorer Dobsonians, available in 8” and 10” apertures, feature an optimized, lightweight mount design and Celestron’s StarSense Explorer technology to help you find your way around the night sky with your smartphone. However, few accessories or other features are included.
Catadioptrics (Visual/Planetary)
- The Celestron NexStar Evolution 8” offers basically the same features as the 8” LX200 ACF at a small fraction of the price, with bonus features like a built-in battery and WiFi adapter and a universal Vixen-style dovetail system to remove the optical tube and easily install it on another mount. The StarSense/EdgeHD version adds EdgeHD optics – superior in performance to the ACF – and the StarSense AutoAlign tool. Neither scope is much better for astrophotography than the LX200 on the stock Evolution mount, but swapping the tube over to a capable German equatorial mount will allow you to shoot deep-sky objects much more easily.
- The Celestron Advanced VX 9.25″ Schmidt-Cassegrain GoTo is undermounted for deep-sky astrophotography but the Advanced VX can easily be used for imaging with a smaller telescope optical tube, while the C9.25 XLT optical tube packs quite a punch compared to a standard 8” Schmidt-Cassegrain without much of an increase in weight or physical size.
- The Celestron CGEM II 1100 offers huge 11” aperture and is extremely capable for planetary viewing and imaging. However, it’s of course unsuitable for deep-sky astrophotography and the 2800mm focal length severely limits the maximum field of view even with a 2” eyepiece, while setup is quite cumbersome compared to a similarly sized Dobsonian. The CPC 1100 GPS features the same optics on an alt-azimuth fork mount like the LX200; it is simpler to assemble but breaks down into fewer and heavier pieces.
Alternative Recommendations for Imaging
Deep-sky astrophotographers should consider a telescope on a German equatorial mount for the task in lieu of a fork-mounted Schmidt-Cassegrain. While a handful of decent astrophotography telescopes are sold paired with good equatorial mounts, in most cases you’ll get a better mount a la carte, and the majority of these telescopes are sold as optical tubes only.
- The Celestron EdgeHD telescopes – available in 8”, 9.25”, 11”, and 14” apertures – provide the same features as the Meade ACF scopes such as field-flattened optics, mirror locks, and a wide illuminated image circle, but are better performers and are compatible with far more accessories such as the Starizona HyperStar f/2 conversion kit. The 8” and 9.25” models make for an ideal pairing with the Celestron CGX mount.
- The Celestron RASA telescopes are essentially EdgeHD units permanently converted to f/2 Schmidt cameras with a built-in corrector system like the Starizona HyperStar. The 8” version is very friendly to smaller mounts while the larger 11” is a beefy but capable choice too. Both are limited in their compatibility with many cameras, however, especially monochrome units.
- Various apochromatic refractors and imaging Newtonians are sold for deep-sky astrophotography; most beginners start with refractors thanks to their simplicity. Check out our OTA Rankings page for more information.
Aftermarket Accessory Recommendations
A dew shield is a good idea for any catadioptric telescope and the 8” LX200 ACF is no exception. A dew shield is necessary to protect the corrector plate from condensation and it will lessen any glare or external light coming into the telescope, while also keeping it safe from dust, pollen, dirt, and debris.
You’ll also definitely want to pick a 2” screw-on dielectric mirror star diagonal such as the one from Apertura, which will allow you to get the largest possible true field of view with this telescope by utilizing 2” eyepieces.
Eyepiece selection is a matter of personal preference, especially if you have a big enough budget to be getting an 8” LX200 in the first place – but at the minimum, you’ll want 3 or 4 eyepieces.
Our top picks would be an Apertura 38mm SWA (53x) to max out the scope’s field of view, a 21mm Baader Hyperion (97x), an Explore Scientific 14mm 82-degree or Baader 14mm Morpheus (145x) and an Explore Scientific 8.5mm 82-degree (239x). The 8” LX200 ACF can take up to 400x magnification under ideal conditions, but this is unlikely to be usable often, and generally magnifications of over around 200-300x are rarely of much utility anyway.
The f/10 focal ratio of the 8” LX200 ACF and most other Schmidt-Cassegrains makes it amenable to nearly all eyepiece types, even fairly cheap designs like Plossls and SWA/Erfle arrangements, so don’t be afraid to experiment.
A Barlow lens can also work in lieu of a high-power, short focal length eyepiece and also is a great accessory to have on hand for planetary imaging.
Additionally, a good UHC (ultra-high contrast) nebula filter such as the Orion UltraBlock improves contrast on emission nebulae through the eyepiece of almost any telescope; a 2” unit will screw onto a 2” to 1.25” adapter if you elect to use the 8” LX200 ACF with 2” eyepieces and thus works with either size ocular.
Lastly, a power supply such as the Celestron PowerTank Lithium Pro or a Westinghouse AC/DC power supply is a good idea if you can’t just plug your scope into a wall outlet; chewing through C batteries is expensive and particularly inconvenient if you run them down during the middle of an observing session.
What can you see?
The 8” LX200 ACF provides the same views as pretty much any other 8” Schmidt-Cassegrain or any good-quality 8” telescope.
- Smaller open star clusters that fit in the field of view, such as M35 or M11, look fantastic. Large clusters like the Pleiades (M45) stretch outside the scope’s maximum achievable field of view and seem lackluster, however.
- Globular star clusters such as M13 and M15 can be resolved into individual stars with an 8” telescope like the LX200 ACF even under fairly light-polluted skies, and I can see the green and blue colors in planetary nebulae like the Blue Snowball and the Cat’s Eye.
- Bright emission nebulae like Orion (M42) and the Lagoon (M8) look decent even from the suburbs, especially with a UHC filter, but are best under dark skies.
- Galaxies are washed-out smudges under light-polluted skies with any telescope, but take the 8” LX200 ACF to a dark sky location where the Milky Way can be seen overhead and you’ll have no trouble resolving dust lanes and other features in many of the brighter galaxies, along with groups such as the Virgo Cluster which may reveal dozens if not hundreds of individual members.
The 8” LX200 ACF is also good for lunar and planetary viewing.
- I’m able to see the phases of Mercury and Venus of course, along with countless tiny details on the Moon regardless of its phase.
- Mars reveals some dark markings and its polar ice caps when the planet is at its closest to Earth, while the 9×50 finderscope easily reveals Jupiter’s moons, which appear as tiny disks with jet-black shadows during their frequent transits of the giant planet. Jupiter itself shows a wide variety of colorful and ever-changing atmospheric details including its equatorial cloud belts, the Great Red Spot, and various smaller storms.
- I’m also able to see the rings of Saturn and the Cassini Division in them, along with a few of the planet’s moons and some tawny stripes in its atmosphere.
- Uranus is a teal disk – you might just barely be able to see a couple of its moons under optimal conditions, but a larger telescope is preferable for the attempt.
- Neptune is a tiny bluish orb and may be hard to resolve clearly at all with the 8” LX200 ACF, but its moon Triton stands out to the keen eye.
- Pluto is too dim for an 8” telescope to reveal even under dark skies due to its increasing dimness as it heads for aphelion later this century; a 10-12” or larger instrument is required to see it as a star-like point.
Astrophotography Possibilities
The 8” LX200 ACF can be converted to an equatorially mounted configuration suitable for deep-sky astrophotography, but this requires the purchase of a heavy-duty equatorial wedge and then precisely polar aligning the scope, as well as adding autoguiding and so forth. Even then, you are unlikely to get the same quality results as a German equatorial mount, all without the option of switching to a different telescope optical tube and with a much more cumbersome and inconvenient setup process.
In any case, an 8” Schmidt-Cassegrain can be a bit of a headache to deal with for beginner deep-sky astrophotographers due to the precise collimation, focus, pointing, tracking, and guiding involved. Smaller instruments, preferably with shorter focal lengths and faster f/ratios, are more forgiving.
As with any 8” Schmidt-Cassegrain, the 8” LX200 ACF is good for planetary and lunar imaging with a suitable 2-3x Barlow lens and a high-speed CMOS video camera like the ZWO ASI224MC, coupled to a laptop with capture software. However, it’s not going to be any different than a cheaper 8” SCT or GoTo Dobsonian at a fraction of the price and a larger aperture scope will beat it in resolving power.
Thank you