Sunday, November 16, 2008


SCTs: The Good, the Bad, and the Ugly

This ain’t got nothing to do with Sergio Leone’s urpic spaghetti westerns, muchachos, but his title seems apt to describe the SCTs us amateurs have been blessed with and inflicted with over the last 45 years. If you eyeball the list, you’ll see we’ve actually been right lucky. The good outnumber either the bad or the ugly. Of course that ain't much consolation if you had the rotten luck to get stuck with one of Meade’s or Celestron’s real faux pas of which there have been a few.

I didn’t dissect every winner and loser here; I coulda gone on and on with Celestron CGEs and CIs and Meade LXDs and LX3s. If you want the entire Straight Poop—as I see it, anyhow—check out my (free) Used CAT Buyers Guide.

The Good

Ultima 8

No, the Celestron Ultima 8 ain’t got the bells and whistles and computers of modern SCTs. In fact it ain’t got a computer despite the fact that for part of its run it was a contemporary of the LX200. What this classic scope does have is good optics and the sturdiest mount ever seen on a mass produced 8-inch CAT. Coming off the Halley debacle, Celestron knew it had to get its optics house in order or risk more bad-mouthing by us amateurs and more lost sales. And man did they do that with the Ultima. Not only were the optics good, they featured Celestron’s Starbright enhanced coatings as standard equipment, something unheard of heretofore. Were these optics better than other early 90s Celestron SCTS? Most folks in the know would say “no,” same optics went into the cheap Classic C8 as in the ritzy Ultima 8, but in my experience the quality of the average Ultimas’ optical set does seem a hair better than that of the Classics and Powerstars of the time.

If it were only the scope's Starbright optics, the Ultima 8 would probably not be remembered so fondly. My own scope, Celeste, could throw up some excellent high power images, but her star test was not perfect. No, it was the “everything else,” the fixins.

Start with what was probably the heaviest-duty fork ever used on an 8-inch SCT. Add a beefed-up drivebase with a heavy-duty bearing system. Naturally, you’d want to do astrophotography with this dog—err..."CAT"—so Celestron threw in PEC. The hand controller was standard equipment too (you would still need to buy a declination motor before taking pix). The tripod was the Heavy Duty Celestron field tripod, in use until recently, but, unlike the tripods shipped with the NexStar GPS scopes, for example, this version’s legs were rubber armored. NO plastic leg spreader for the Ultima either, nosir buddy. Initially, Celestron furnished the scope with a wedge not much different from the one shipped with the Powerstar. That proved way too light for this hefty U8, though, so Celestron soon upgraded to a modified C11 wedge. The cherry on top? A custom near-airline-shippable case (mine is still in A-OK shape despite having travelled many a mile).

LX200 Classic

The LX200 (most of us amateurs call it the LX200 “classic” to distinguish it from the later LX200 GPS) was not there first with goto. The laurels for that belong to Celestron and its Compustar series. The LX200 was the scope that made goto reliable and affordable, however. Combine a computer system that worked consistently and was reasonably forgiving of less than perfect polar and go-to alignments with a near-Ultima quality fork and drive base and tripod and, yeah, suddenly Meade was no longer the SCT-buyin’ amateur’s second choice.

I still remember my first exposure to the LX200, a 10-inch model (by the end she was available in apertures of 8, 10, 12, and 16-inches). I was skeptical, way skeptical, about my friend Dave's decision to spend his entire income tax rebate check on this beast. Goto? Outside a professional observatory? Forget it. Computers at this price point just couldn’t work right, could they (I had just moved up to a real IBM from my Commodore 64 and my bank account was still hurting)? David powered up, mashed a few buttons, the telescope hummed (well, more like ground) and stopped on what it said was M5. My skepticism ended when I put eye to eyepiece. Yep, that big-daddy globular was centered and looking real good.


Let’s face it: even us blue tube fanciers will admit Meade has had its ups and downs product introduction-wise. The LX200 GPS skated on thin ice for a while, and the RCX 400 fell through it. Out of all Meade go-to scopes that have come and went, the LX90 is the one that suffered the fewest growing pains. It just worked.

Meade must have been somewhat nonplussed that the 90 was more trouble free than the flagship LX200 GPS, and that was likely reflected in the fact that they always crippled the 90 slightly for astro-imaging. Not only was there initially no PEC or PPEC, the LX90 didn’t even have an auto-guider port. The latter could be cured by the purchase of an add-on module, but PPEC never was added (oh, the latest models have PEC, but, strangely, the auto-guide port module has now been discontinued). The reason for this skullduggery was clear: despite a somewhat undersized fork, this little scope-that-could had such a good reputation and performed so well that the addition of PPEC would have meant quite a few customers would have chosen this one instead of the (more expensive) LX200 and LX200GPS.

A rather sad postscript to this tale is that Meade is currently having serious drive problems with new LX90s, brought on, I reckon, by their move to down Mexico way. Shame.

Celestron Orange Tube

This is the telescope that changed everything. In 1970 Celestron (Pacific) decided there was money to be made off Joe and Jane Amateur Astronomer. Oh, the company had been selling SCTs for a while, its graceful and expensive Blue and White Tube jobs. Nice as they were, these kitties were not priced to appeal to amateurs, though many amateurs, including the not-so-old at the time Unk, wanted one. Bad. The curious thing (like the dog in the night) is it took Celestron as long as it did to decide that, yes, the SCT might be the perfect for the average amateur.

By the dawn of the 1970s, more and more folks had to travel to escape light pollution, were interested in imaging, and had to load the telescope into a Ford Pinto or a Chevy Vega. A Cave Newtonian no longer filled the bill. Those big honkin’ scopes were not only a pain to stuff into an oil crisis special like a Ford Pinto, they often had to be heavily modified to support picture taking. The SCTs, in contrast, were compact and imaging-ready (well almost). If only one didn’t cost as much as the Pinto it would be riding in.

A few cost cutting measures (simpler drive system, cheaper focus system, tripods instead of massive piers) and some orange paint and the amateur SCT arrived. This telescope was around for over 12 years, and though it went through a few changes (mainly goin' from the beautiful sand-cast fork to something quicker and cheaper to produce), it remained the most wanted amateur telescope until it was finally dethroned by the Super C8 in the early 80s.

Celestron Pacific C10

Like the LX200, this is one of the telescopes I’ve always wanted but never got around to getting. Why I didn’t buy one back in the 60s is, as above, easy to explain: a C10 cost about what you would pay for a brand-new VW beetle. Not that that wouldn’t have been worth it if you had the cash. In addition to its surpassing good looks, this telescope has some features not exceeded in a commercial SCT till the birth of the ill-fated RCX 400. In addition to a good and accurate (AC of course) drive, and a very stable mount and pier (heavy), this scope has one thing modern SCTs don’t have, a zero shift moving mirror focusing system.

Like current CATs, the CP C10 focuses by moving the primary mirror. This was one of the Celestron innovations that made the scope imaging-ready (no need to reposition the primary mirror or spider/secondary before the camera would come to focus as with a Newtonian), and they did it right. Today’s Meade and Celestron mirrors are moved in and out by a single threaded rod screwed into the primary mirror holder. Since the mirror is being pushed and pulled only on one side, it naturally wants to tilt a little on the baffle. The result is focus shift. The Celestron C10 and other White and Blue scopes, in contrast, used three connected focusing "spindles." No focus shift would you see on this CAT, Skeezix. Add excellent sweated-over optics to the mix, and you will understand why I’ve been admiring these ground-breaking scopes (and their 8, 12, 16, and 22-inch sisters) from afar for over 40 years. Want the complete skinny on the Blue and Whites? No better place to get that than my friend Bob Piekiel’s wonderful e-book Celestron: The Early Years (check Astromart for his ads).

Meade 2080

I was skeptical about the Meade 2080 when she debuted in 1980. Ho-hum. Just another bunch of dudes like Criterion (see below) trying to cash-in on Celestron’s SCT success. I figgered the scope would be punk if not junk. Surely, nobody could out-SCT Celestron, could they? Somebody could. John Diebel was his name. Like Celestron’s Tom Johnson, he was a southern California electronics engineer who dreamed of producing world-class telescopes. He’d has some success with good but reasonably priced Newtonians, but it was obvious SCTs were the wave of the future, and John decided his little company, not far from the kitchen table stage, would make one.

What came out of Costa Mesa was something not just as good as the still-current Orange Tube; in at least one way it was better. Lots of amateurs took lots of good deep sky images with the Celestron, but there was no doubt the scope’s drive gears didn’t make that easy. Like all spur-gear drive units, it was a little jumpy. You had to watch not only for periodic error, but for random excursions, making guiding a somewhat hair-raising experience. The 2080 was revolutionary in that the smaller drive gear was a worm gear, resulting in somewhat better tracking and considerably less “noise.” The scope with its gleaming dark blue finish also looked modern, while to our eyes the orange Celestrons were beginning to look “old” rather than “classic

The Bad


Most of the telescopes in this section might just as easily labeled “not quite there,” “almost,” or “ahead of their time” instead of “bad.” Not the Halleyscopes. Wut’s they-at? A “Halleyscope” is a Meade or Celestron SCT produced during or following the passage of Comet Halley back yonder in the 1980s. Roughly 1987 – 1992. During the flowering of Comet Halley, both companies cranked-up production to “11,” and consequently wore out their tools and their workforces. Kinda for naught, too, since Halley was hardly the spectacle telescope sellers dreamed of.

In the lay-public’s eyes, anyhow, the renowned visitor was a big bust, and not long after its less than earth-shaking passage, all the Halley books, shirts, soft drinks, candies, gum cards, bumperstickers and other gimcracks sat forlorn in the bargain bins. Telescopes? Dealers quickly saw the handwriting on the observatory wall and began cancelling their over-optimistic orders with abandon. Meade and Celestron had imagined not just huge sales during the comet, but after. The spectacular Halley would finally take amateur astronomy mainstream. When the dust cleared, M & C weren’t just worn out, they faced some real economic hard times. It took ‘em, in fact, darned near five years to clean up their acts following the comet mess.

What exactly is bad about Halleyscopes? Could be anything. When you rush production like they did, QA goes out the winder. What is most often bad with scopes of this age, however, is their optics, and specifically their correctors. Are all Halleyscopes bad? No. But. If you are considering buying one follow Ronald Reagan’s uncharacteristically sage advice and “Trust but verify.”

Celestron Ultima 2000

The Ultima 2000, known to its fans as the “U2K,” definitely falls into the category of “almost there” or “ahead of its time.” This was to be Celestron’s answer to the ever more popular LX200. Unfortunately, by the time it finally appeared in the mid 90s, the Meade was so entrenched that it would have taken one heck of a lot to dislodge it. Sadly, while an interesting and even endearing scope, the Ultima 2000 was simply not a good SCT. What was delivered was, for one thing, not quite what we had been promised. Initially, Celestron had made lotsa noise about an “innovative roller drive” for the scope. That would have eliminated final drive gears and more-or-less banished periodic error. Unfortunately, the C gang could not get that to work right. Instead, it was furnished with a worm drive system no better or worse than what was in the Ultima 8. The final product did have some interesting features, however,.

The nicest of these was that the scope’s position encoders were separate from its motors. What that meant was that you could align this CAT, and then, if you had a mind to, grab the tube and slew it by hand anywhere in the sky without losing your go-to alignment. The Ultima 2000 was also a very light scope; the one we have at the University here is easily transported and setup by smaller women students. The go-to computer system (Tom Johnson’s son and Tangent electronics developed it) was very simple and non-intimidating for novices to learn and use. Finally, this was the last Celestron shipped with a real case.

If there were no bad in the U2K, its descendants would be with us today. Instead, Celestron switched gears about five years later with the much more LX200-like NexStars. So what was the bad? There were plenty of aggravations as well as pleasures. Yeah, it was nice to be able to grab the tube and move it by hand, but to make that practical, the scope used clutches instead of locks on both axes, and these clutches had to be adjusted correctly and were finicky. Yes, the go-to system was simple to use, but Celestron maybe went too simple with the HC, which was much more like a Tangent DSC box than the LX200 controller. Many functions were done by a few buttons and quite a few owners felt like they were always pushing the wrong one at the wrong time.

Last nail in the coffin? The go-to accuracy was more similar to what could be expected with DSCs than with an LX200. And the scope was afflicted with the dread year 2000 bug. Yep, the U2K had Y2K. That meant that after 12/31/2000 the planets would always be "off." Celestron appears to have released a replacement PROM chip to cure this (and one to make the telescope’s non-functional PEC work), but by that time they got around to that, most owners and potential owners had just moved on.

Celestron Compustar

Yep, Celestron was there before Meade with go-to scopes. In about 1987, to be exact. The Compustar 8 (and its 11 and 14-inch companions) hung on into the 90s, but were never real competition for the LX200s. Why not? In this case, “ahead of their time” also meant “expensive.” When most amateurs balked at paying 2000 for a top-o-the-line 8-inch, the C-star 8 demanded 3500 great big 1980s dollars.

The SCT was also not quite there technologically. It did have a very nice and functional hand controller, maybe the nicest ever seen on a go-to SCT, but its object finding acumen was sometimes less than stellar. It helped to have a dead-on polar alignment. Which meant the scope could be a bit of a pain to setup for portable field use.

Despite these foibles, a well-maintained Compustar can still impress. Back then? One, in some ways, blew the doors off the early LX200s. For example, the C-star included a library of 8,000 objects vice the initial LX200’s 747. And despite the LX200's good build quality, that of the Compustar was noticeably better. If only Celestron had continued to improve and build-on the Compustar instead of goin’ off the rails with the U2K. But they didn’t.

Meade LX50

Why was there an LX50? Because nobody much liked the LX100, Meade’s non-go-to version of the LX200. Not only would the LX50 be less expensive than teh LX100, it would even offer semi-go-to via the optional Magellan II system. Folks who couldn’t afford or didn’t want real go-to would flock to the scope in droves. Initially they did. There are quite a few things to like about this 90s CAT. The optics, especially 10-inch optics, are almost always good, and the scope features a near Ultima-8 hefty tripod and fork. Sadly, the not-quite-theres of the 50 meant nobody much cared when it was replaced by the LX90.

Warts? The LX50 had plenty. To begin, it “featured” aluminum drive gears which tended to land astrophotographers in PE hell. Meade soon replaced the initial components with better ones, but the bloom was off the rose by then. The declination gear system was also purty lousy—a small (now gone) and well-regarded company, Scopetronix, first entered the bidness as a purveyor of “dec fix” kits for the 50. Magellan II? It sometimes worked OK as a DSC system, but the semi-go-to feature never was completely functional. Semi-go-to? Yep, the DSCs would lead you to within a degree or two of the target, you’d push a button, and the RA and dec motors would drive the LX50 the rest of the way. Why did this not work? Apparently because of conflicts between the firmware in the scope (yes, this “manual” SCT had some), and firmware in the Magellan II hand unit.

Celestron Celestar Basic

I genuinely hate to put this little telescope in the “bad” category. In many ways this latter day non-go-to was nice. It was light, had good optics (most of the time), and was considerably better-finished than Meade’s competing LX10. It was mostly a visual scope, with no dec motor nor hand controller being included, but good pictures were taken with it. The drive, while not a paragon of accuracy with its spur gear set was mostly OK.

Unfortunately, Celestron used a stepper motor rather than the customary servo motor. Today, that ain’t a bad thing. On a cheap 90s scope? You could sometimes see the drive “stepping along” at high magnifications. Top it all off? Rather than a separate wedge and tripod, to save money on this successor to the Classic C8, Celestron used an abortion they called the “wedgepod.” That was a cheap, light equatorial wedge with the tripod legs fastened directly to it. Yeah, it was light and easy to carry around, but the only way to adjust it in azimuth for polar alignment was by kickin’ the durned legs to nudge it.

The Ugly

Meade RCX400 (LX400-ACF)

Like the Meade LX6 which follows, the RCX 400 (available in fork-mount apertures of 10, 12, 14, and—supposedly—16-inches) was not a bad idea. It was a very good idea. What you had in the RCX design was an f/8 aplantic SCT design that produced noticeably better-looking stars at the edge of an eyepiece field—or imaging chip—than a “standard” SCT. This good optical design was ably assisted by a fork mount/OTA that provided most of the things we amateurs has asked—nay, begged—for for years: true zero image shift focusing, USB connectivity, a built in corrector heater, and more. What killed this good idea was poor execution and poor QA.

What surprised me about the RCX I had a chance to use? Despite a price roughly twice what Meade charged for a standard scope, in some ways the RCX exuded cheapness. The motors, both on the RA and dec drives and on the focus system had that slot-car-motor sound, and the fork and drivebase looked as if they had been sandcast is somebody's backyard. At least the example I tried worked and worked well. Many RCX buyers were shocked and disappointed by telescopes either dead out of the box (minimalist QA) or which gave up the ghost soon thereafter (cheap components/poor design). The motorized focus/collimation system seemed a particular problem, with malfunctions there being distressingly common.

I’ll reiterate: the RCX400 was a great idea. The telescope had real potential, and had it been better executed or if Meade had had the resources to fix the “not goods” this would no doubt be my—and a lot of other amateurs’—favorite fork mount SCT today. As it is, it is one of the least dependable commercial telescopes ever made, and is to be avoided. Game over, end or story, zip up your fly.

Criterion Dynamax

I can sum-up the “quality” of the Criterion SCTs simply: I have never, ever seen one that was optically better than “fair.” Why is that? Criterion is a company famous in the annals of amateur astronomy for producing very high quality Newtonian reflectors at reasonable prices. Why couldn’t they do the same with SCTs and provide real competition for Celestron back in the 1970s?

The stumbling block was the corrector plate (lens). The company stumbled in attempts to mass produce correctors without infringing on Celestron’s patents. When the legal smoke cleared, and Criterion found away to do those all-important lenses, they stumbled again. Rather than matching the optics to make sure correctors, primaries, and secondaries worked well together, Criterion just assembled scopes out of whatever came off the assembly line first. That was what killed ‘em, and why these telescopes are nothing more than historical curiosities usually not worthy anybody’s time much less money.

Meade LX6

Like the RCX 400, the LX6 was a good idea, but one that didn’t turn out as planned. The idea was to build an SCT that offered wider fields and faster imaging via an f/6.3 optics set. What make this good idea less than a stellar success? Several things. First, it took Meade a while, apparently, to get the hang of doing fast SCT optics. By the mid 90s they were turning out some f/6.3 LX200s that were stellar performers. That was long after the manual, non-go-to LX6 (much like the previous LX5) was history, however. Also, coming on the heels of Halley, I suspect Meade’s optics department was just not up to the task of doing f/6.3 when they were struggling with f/10. The most amusing part of the LX6 history? Astronomy Magazine, when they reviewed the scope, had to request three different examples before getting one with passable optics. In Astronomy’s defense, at least they informed the reader of this fact. Ah, well.

That, then, is my SCT gallery of fame ‘n shame. Did I step on your toes? Do you love your wonderful LX6? Has your RCX been TROUBLE FREE FROM DAY ONE? That ol’ Dynamax is the best scope you have ever owned? Keep in mind I must speak in generalities. There are certainly good RCXes. I’ve seen some right good LX6es. I even theorize there are some good Criterions out there—somewheres. If your telescope performs for you, and you are happy with it, that’s what matters, not its pedigree or what silly ol' Unk Rod thinks.

I saw an ad on astromart for a brand new SCT ( It is aparently coming out of China and isn't round, from the photos it appears to be a pentagon.

Any comments?
The bad scopes LX50 and Ultima 2000 shortcomings can be partially remedied with a notebook PC running telescope control software. I got a LX50 and an Ultima 200 to work fine with TheSky version 6. This enabled me to ignore the Ultima hand controller Y2K bug and the shortcomings of the Magellan II on the 50.
I have come back to amateur astronomy as a hobby after almost a 20 year absence.

Recently I acquired a Celestron Ultima 2000 mount which I have mated to a Celestron C-8 OTA which was not originally an Ultima 2000. It does not have the "downstop" on the end of the telescope tube.
Is there a way that I can accurately set the scope to the downstop position for alignment purposes with the downstop not being present. I was thinking that perhaps a bubble level indicating true vertical of the OTA might be a possible answer.

Any suggestions are greatly appreciated on how I might get a good alignment without benefit of a downstop on the OTA tube.

Needless to say due to the age and “mongrel” pedigree of my scope Celestron chooses to be of no assistance. Any resources that you know of that might be of assistance for either information or professional columniation of the computer guidance system of this set up is greatly appreciated


Gene Middleton
Yes, I'd try your bubble-level idea.
Criterion scopes were awful, Bausch & Lomb should have stuck with cheap refractors and backyard-built Newtonians.
But then even early celestrons like the 10" were junk as well. More proof hand-working optics unless you have the time and profit built-in, is a waste of time.
Funny, no information about Ultima 8's whacking into the hand control plug with the fork-arms?
Hi Richard:

Hmmm...well...let's see. Most of the B&L scopes were as bad as the Criterions. But not the 8001 Pro. It was really excellent and could have been a sign of what the company could have done if they hadn't decided to throw in the towel and close their new factory.

Celestron Pacific? The C10s I've used have been nothing less than optically excellent. Were there some poor ones? Maybe. They were still working on the details. Still, the optics were not handmade. Johnson was already using his master block method.

Not sure what you mean about the Ultima 8. I used one for over a decade and never had a problem with the cord (mine was a 1995 model)...
I just recently became an owner of the Celestron Celestar on a wedgepod. I do not like the wedgepod especially being an EQ user for years. So I put a dovetail on the 8" SCT and now this is my favorite scope. I've only owned news before, so this is a whole new ballgame for me. The only thing bad about the celestar is that wedgepod. I wonder if it's worth any money, as I'll probably not be using it.
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