Celestron's and Meade's midgrade SCTs, the LX90 and the C8 CPC, are a definite step up from the basic telescopes. They are not much better accessorized than the low-cost models (Why is it that an imported Dobsonian is often equipped with two or three eyepieces, while much more expensive SCTs come with only one?), but the ills that plague the price-buster scopes have been at least partially cured. Most notably, the gear systems on these SCTs are much better; they exhibit far less annoying backlash than the LXD75, C8-SGT, and especially the NexStar 8 SE. The midgrade mounts are also less shaky, and both brands are equipped with PEC to make imaging easier. All this goodness comes at a penalty, however. These telescopes are heavier, if still transportable by any healthy adult. They are also more expensive. At the midlevel, plan to pay about $2,000 for a scope. Still, this seems very reasonable considering the capabilities of these CATs. One of them could very well be the scope of a lifetime ("aperture fever" notwithstanding).
When Meade announced the LX90 SCT toward the end of the 1990s, amateur astronomers were a little skeptical. The fact that that this telescope, which would replace the company's non-go-to LX50 model, was to be equipped with the Autostar computer, the same HC that was introduced with the company's go-to ETX telescopes, seemed a recipe for disaster. What Meade would do, it seemed likely, was scale up the tiny ETX 90 MCT to 8-inch size. It would have all the plastic of its little brother, but since it would have 8-inches of telescope aperture onboard, it would be as shaky as a leaf in a Gulf of Mexico hurricane. Nobody in their right mind would buy the thing. Wrong!
The LX90 was an immediate and continuing hit with amateur astronomers and for good reason: its outstanding design. The telescope simply does what it is supposed to do, simply and reliably. The Autostar computer—variations of which are now used on all Meade's go-to telescopes—means it is full featured. In fact, most observers will never get around to making use of all its capabilities.
The LX90 is currently priced at $2,000, putting it squarely in the midprice pack. As seen in Plate 16, it has that classic SCT look. Unlike the Celestron SE, it has a double-tine fork mount. There are no fancy paint jobs; the LX90 is finished in the same good old Meade blue-and-black color scheme the company has been using for the last 30 years. A look at the base of the right fork arm reveals a group of telephone-style RJ-11 connectors and that spells "go-to"—and does it go-to. The LX90 features a built-in library of 30,000 DSOs, planets, and stars, just like the LXD75. Worried about exhausting those 30,000 objects In that unlikely event, the scope
Plate 16. (8-inch LX90) Meade's mid-price 8-inch SCT, the LX90-ACF. Credit: Image courtesy of Meade Instruments Corporation.
can be hooked up to a computer via an RS-232 connector in the Autostar's base and utilize an astronomy software program's library of hundreds of thousands or millions of objects. If you do not want to spend money on astronomy software needed to control a telescope, that is okay. Meade throws in a copy of its Autostar Suite software with every LX90.
If long-exposure deep sky imaging with the LX90 is a goal, be prepared to spend more money, and not just for a camera. Meade's optional LX90 wedge is a must buy for versatile imaging use of the scope. As delivered, this CAT, like other fork-mount telescopes, can only be set up in alt-azimuth fashion directly onto the head of its tripod. The LX90 cannot use just any Meade wedge; it requires the Meade wedge designed specifically for the 90 (the LX90 has only one bolt hole in its base rather than the normal three) or Meade's "wedge adapter plate," which will allow the LX90 to be mounted on a standard Meade wedge. It is not known why Meade did not just put three holes in the drive base.
When it comes to included accessories, the LX90 is not much advanced from the el cheapo brigade. Other than the aforementioned software CD, there is a 1.25-inch, 26-mm Plossl eyepiece (good enough) and a star diagonal. One nice touch is that the telescope ships with a high-quality 50-mm finder telescope in addition to the red-dot LNT finder/module that Is used for initial go-to alignment. As is the case with most other Meade CATs, the enhanced UHTC optics are standard.
Other than relatively minor software changes, the LX90 remained the same for quite a few years. Then, beginning in 2005, Meade piled on the new stuff. In addition to introducing larger-aperture LX90s, a 10-inch and a 12-inch, it added GPS to the 8-inch LX90. Coupled with the scope's north-and-level alignment routine, the GPS makes go-to alignment a true no brainer: Turn on the telescope, and it listens for GPS satellites, gets a "fix"—determines time and the scope's current location— and does a little dance. The tube levels itself, finds north, determines the tilt of the scope tripod/mount, chooses two alignment stars, and heads for the first one. All the user must do is center the alignment stars in the finder (either the red-dot LNT finder or the real finder scope), hit enter, and the telescope is ready for an evening's sky voyaging.
The LNT red-dot finder is a pleasure to use for alignment. Since there is no magnification, the field of view is wide, making it easy to get the alignment star centered. One other nice thing about the LNT: When the alignment begins, the Autostar HC automatically turns on the red dot. When alignment is done, it turns it off. Many times a red-dot finder's small batteries have been burned out by forgetting to shut the thing off in the excitement of starting to observe.
One other feature that makes LX90 go-to alignment easy is that the user does not have to set the mount or tube in a special "home position" before beginning. Unlike most of Meade's other go-to telescopes, the LX90's receptacles for the hand control, power, and other cords are in a fork arm and not in the base, so there are no cables running up from the drive base to the fork to twist if the scope is rotated too far in one direction. There are no "hard stops" needed in the base to prevent this rotation, and the scope does not need to be made aware of its rotational position in reference to these stops at startup by placing the tube in a particular starting position. Plunk the LX90 down with the tube facing anywhere, hit the power, let it do its dance, and it is good to go.
The LX90 is a remarkably well-designed scope. However, your Old Uncle Rod can always find nits to pick with any SCT, and the LX90 is no exception. One negative thing about this telescope is its elevation/declination lock knob. It always feels too loose, but the user may be reluctant to tighten it down too much for fear of breaking something. In the scope's defense, while the knob felt too loose, it always seemed to hold the scope firmly in place in declination. The problem was merely "feel." Then, there is the fork. The LX90's fork mount is hefty enough for extensive visual use and some imaging, but it could not be called rock solid. Do not expect to do 2-hour CCD exposures in the middle of a windstorm.
Astrophotographers will be pleased to learn that, like the LXD75, the LX90 Autostar includes PEC. It is unfortunate, though, that this is PEC and not PPEC, permanent periodic error correction. Meade's more expensive models allow guide corrections to be recorded and stored permanently. As is the case with the entry-level LXD75, unfortunately, an LX90 PEC recording is erased at power down and has to be redone for every imaging session. That is a shame since the LX90 is otherwise nicely suited for astrophotography. A shame, but not a show-stopper. One other feature of interest to astrophotographers the scope lacks is a dedicated autoguide port. That can be fixed with the addition of the Meade 909 accessory port module (about $50), or the scope can be guided through its serial port with the proper software.
Another quibble concerns, as usual, the telescope's power arrangement. As with the Celestron SE, the telescope can be powered by internal batteries, eight C cells this time. Although that might be a minor step up from AAs, Cs will not last long, either. Get the optional DC cable and run the LX90 with a reliable lawn tractor or automotive "jump start" battery. Meade really should face the realities of the power situation and begin including the necessary DC power cable instead of making new buyers pay extra for it.
Do not take the foregoing to mean that we do not like the LX90. Its pluses far outweigh its minuses. This is a well-thought-out, sweet little scope sure to please both beginners and advanced amateurs. In fact, there may not be another SCT that is both as easy to use and as capable of carrying out demanding observing programs.
Just as this book was being finished, Meade announced yet another version of the venerable LX90, the LX90-ACF. This new edition is identical to the previous LX90-GPS, but the standard SCT optics have been replaced by Meade's f/10 Advanced Coma Free optics package. For more details, see the entries on the LX200-ACF and the LX400-ACF, but in a nutshell, these aplantic SCT optics can produce flatter fields and sharper stars.
When Celestron began to put itself back together following its economic problems of the late 1990s, the SCT that re-won the company the hearts and minds of amateur astronomers was the NexStar GPS. These heftily mounted fork scopes equipped with built-in GPS receivers took the amateur community by storm. Alas, nothing lasts forever, and we knew Celestron would eventually have to retire these classic CATs. The question was Celestron would do for an encore. The GPS was a tough scope to follow.
What Celestron did was introduce a fork-mount CAT that was a lot like the NexStar GPS, but with some hardware and software refinements. The CPC 800 8-inch ($2,000) model, shown in Plate 17, features a larger drive base and RA gear system, an improved tripod, and updated firmware that includes the new SkyAlign routine (see the entry for the NexStar 8 SE). In fact, one of the main reasons Celestron may have introduced the CPC when it did was to make a clean break with the old north-and-level GPS scopes. Every GPS scope sold meant a royalty payment to Meade for the use of the north-and-level routine.
Celestron's mid-price entry, the CPC 800 8-inch SCT. Credit: Image courtesy of Celestron.
What is a CPC like? To be honest, it is not as attractive as the GPS models. The base is absolutely huge in comparison to the 8-inch OTA. That may be good for tracking, but it looks kind of funky. Then, there is the color scheme, silver-gray base, black fork arms, and gray aluminum tube. Something just does not work there. By the way, CPC supposedly stands for "Celestron Professional Computerized", whatever that means. Like cats, all CATs look alike in the dark anyhow, and you can call your scope anything you want. What matters is how a CAT performs on the observing field.
Optically, there were no surprises. Celestron seems to have been on a roll in that regard over the last 10 years or so. There does not seem to have been an optically inferior Celestron OTA produced in a long time. Equipped with the (standard) Star-Bright XLT optics, this OTA should whip—at least slightly—even the Ultima 8 OTA. Other than that, there is not a lot to say about the tube. The OTA has been slightly redesigned (all Celestron's OTAs have), but this seems to be for appearance only. Build quality, including focus action, is still very good.
The mounting, despite its wacky color scheme and big base, is very much like that of the NexStar GPS scopes. There are two sturdy aluminum (plastic-covered) fork arms. The base has RJ- (telephone) style inputs for the HC, PC (for NexRemote), and "Aux." What are the uses of Celestron's Aux inputs? Not much. Celestron promised us "numerous Smart Accessories" would "soon be available" to use these connectors, but it has been 6 years since these plugs appeared, and no Smart Accessories have appeared on the scene. One of the most wonderful things about this mount is that it is like a radar antenna. How so? It uses a slip ring to transfer power and data from the base to the fork. This arrangement, like that used for rotating radar antennas, means that there are no wires to get twisted. Signals are conveyed by two rings rotating against each other. For this reason, Celestron does not have to either put the connectors in a fork arm or use hard stops, as Meade does.
What makes that base so darned big? This is Celestron's take on an SCT RA drive. The tube is driven by a worm/spur gear set just like Meade's scopes. The CPCs differ in regard to what the mount moves on. Instead of a ball-bearing race, Celestron's CPC mount uses rollers riding in a large-diameter track. That makes for smooth azimuth/RA movement. The only real complaint about this system is that over time the NexStar GPS (which uses a similar but slightly smaller track) gets dirty, making movement a little rough and herky-jerky. The track is fairly easy to clean, however.
The CPC uses the same HC shipped with all Celestron's other current go-to scopes (programmed with CPC software). The NexStar hand control contains over 40,000 objects, tours, and space for 400 user-defined objects (like comets, etc.). Again, the main complaint about the HC is the black-on-red display, which is hard to read at 3 a.m. with middle-aged eyes.
One word sums up the drive system on this scope: solid. Celestron uses high-quality servomotors. You often hear long-time amateurs joke about the coffee grinder noise made by go-to scopes on a peaceful observing field—no java with this one. Even slewing at high speed (3° per second maximum), the sound is more like the purring of a big cat than a refugee from Starbucks.
In the area of included accessories, the scope is similar to the less-expensive Celestrons (and the Meades). Included is an inexpensive Plossl (a not-so-hot 40 mm) and a similarly inexpensive 1.25-inch star diagonal. Both these items work okay but are destined to be tossed in a drawer and forgotten as soon as something better can be purchased. There is also a good 50-mm finder and a CD containing the all-important NexRemote software. Way down in the Styrofoam peanuts is one last item: a DC power cable. It is unclear why Celestron does not include this cord with all its SCTs. Encouraging users to power the scope with a reliable 12-volt DC power source would prevent a lot of "tech support" calls to the company. The CPC tripod is Celestron's improved heavy-duty field model (chrome) with 2-inch steel legs. This is at least an incremental advance over the Celestron "heavy-duty" tripod of yore.
"Ain't nuthin' perfect on God's green Earth," as Rod's old granny used to say, and the CPC is not exempt, even if there is not too much bad we can think to say about this one. It was disappointing to see that this series of scopes uses aluminum tubes rather than the carbon fiber of the NexStar GPS series. Carbon fiber was both elegantly attractive and a boon for imagers. It does not expand or contract very much with temperature changes, meaning astrophotographers do not have to refocus NexStar GPS telescopes very often. Aluminum-tubed scopes do have the benefit of reaching thermal equilibrium faster than carbon fiber ones, though, and being able to get the scope settled down for viewing quicker is probably of more interest to most observers than avoiding tiny changes in focus.
The only other criticism is not really a criticism per se. The CPC is a very good fork-mount telescope, but it is a fork-mount telescope, and a comparably priced GEM seems a better investment if astrophotography is a major interest. The CPC is certainly as imaging capable as any other fork scope and has an advantage over the LX90 in that it is equipped with PPEC. Like other current fork-mount scopes from both Meade and Celestron, a wedge, required for long exposure photography, is optional for the CPC. Like the SE, the entire CPC is now apparently being produced offshore in China. Also, as with the SE, quality does not seem to have been affected.
Despite its odd looks, it must be admitted that the CPC is a worthy successor to the GPS scopes. It is at heart very similar to those classic instruments and can certainly give a lot of pleasure as a general-use or even an advanced-use CAT.
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