TeleVue Ranger vs. Celestron FS80WA Small Scope Shootout!
Updated 10/24/99
Wanted: Small, Portable Telescope to Deliver Clean, Bright Views at
a Moment's Notice.Large enough for serious use, but small enough for most budgets and living spaces, quality portable scopes are the hottest ticket going in amateur astronomy. Even those of us with huge light buckets need a quick-peek scope for those nights when we don't have the energy to lug out the Big Gun, or for those marginal evenings when we're not sure if the skies are going to clear up or open up. And when astronomers pony up to buy a quick-look scope, what do they buy? More often than not, they buy a refractor. If we're going to have to live with a small aperture, we at least want sharp, contrasty images. Call it a tradeoff between quantity and quality. You will find a lot of variety at this niche and price level, but the market has consistently voted, during the past few years, for two humble refractors from Celestron/Orion and TeleVue. So, how did these little scopes check out? Was the secondary spectrum on the Celestron intolerable? Is the Ranger worth the extra money? How well do they take high magnification? I've been observing through a number of samples of each scope for over a year now. Since I now own both scopes, I spent several nights comparing them, and came to some conclusions. So rustle yourself up a chair, read on, and see what I found... In this corner... TeleVue's Ranger, a down-scaled version of its perenially popular Pronto, sports an air-spaced 70 mm f/6.8 lens, using an ED glass element. Replacing one of the traditional elements of an achromat with ED glass should reduce its false color by a factor of three or more. Also, since ED glass transmits a higher percentage of the light passing through it, it effectively "increases" the aperture of the refractor on which it's used. Indeed, the Ranger/Pronto duo behave like much larger instruments. Unlike the Pronto, the Ranger does not have a 2" visual back. Also, the smooth rack-and-pinion focuser has been replaced by a well-made, but somewhat incon- venient helical focuser, like on a telephoto lens. The nice, screw on metal dust cap on the Pronto got deleted, as well. The upside to all of this is that the 6.6 lb weight of the Pronto got hacked down to 3.5 lbs -- a remarkable acheivement, considering that the optics on both scopes are identical. I measured the "real world" weight of the Ranger (with diagonal, Quik Point finder, 25 mm Plossl, and Bogen release plate) at 4.25 lbs., which means it's suitable for mounting on moderate photo tripods. The Ranger sells for about $600-$700 street, depending on options. And in THIS corner... Like the proverbial man without a country, Celestron's FS80WA wanders from manufacturer to manufacturer, changing nameplates as it sees fit. The scope appears to be a Vixen. The objective lens looks like a Vixen design, and the visual back/ finder holder are definitely sourced from Vixen. The scope first appeared as the Orion Short Tube. Selling for $249, the scope came with a 45 degree diagonal, 25 mm and 10 mm Kellners, finder, and a 1/4" X 20 plate on the bottom of the OTA. And if you have any doubts about the popularity of small refractors right now, note that in mid-1997, Orion reported a backlog of nearly nine months on this little scope. Soon after the introduction of the Orion product, Celestron began advertising its FS80WA, which turned out to be the same scope, painted black instead of white, carrying a 90 degree diagonal and mounted on Celestron's lightweight equatorial mount. The tripod socket has been replaced by a quirky (metric) two-bolt mounting system that has been driving me nuts as I'm trying to convert mine to Alt-Az operation. The Celestron version listed for $349, which would seem like a bargain compared to the Orion version. But things got even better. The FS80WA was routinely discounted by retailers; at this writing, the street price on this unit has fallen to about $300. In other words, customers could get the complete equatorial mount and 90 degree diagonal for only about $50 extra. Finally, to complicate matters even further, some FS80WA's are now shipping without the finder. The argument goes that the scope has a wide enough field in its own right. Still, I can report that it's a definite advantage to have the finder. Some retailers still stock finder-equipped FS80WA's; ask. There is a least one other version of the same OTA, sold under the Vista name in Canada. For $190, you get the optical tube, tripod socket, diagonal, 20 mm Plossl, and finder. Apogee sells the same scope without diagonal or eyepiece, also for $190. And I have seen a Vixen version in British astronomy magazines that appears to be the same scope. There will be a quiz on all of this later. The business end of the FS80WA is an 80 mm f/5 doublet. The dark green coatings are reassuring, and a surprise at this price point. The finder is a 6X30 unit that you see everywhere on Celestron scopes. The Vixen focuser is extremely smooth, but not as smooth as the one on the Ranger. Despite looking larger and bulkier than the Ranger, I measured the "real world" weight of the FS80 (OTA with finder, diagonal, and 25 mm Plossl eyepiece) at only 3.75 lbs., about half a pound lighter than the Ranger. Meanwhile, Back at the Ranch... I set the scopes up side by side on several consecutive nights and did some observing. The Ranger sat atop a Bogen 3001/3030 combo, while the FS80 assumed its position on the supplied equatorial mount. I also fashioned a wooden adapter plate that allowed me to use the FS80 on the Bogen setup. Draw... The Ranger was up first. Your first impression of TeleVue's smallest telescope is one of solidity and rigidity. It feels as if it was carved out of a solid chunk of steel and glass. The fits are tight, the quality of the hardware is extremely high, and the parts that move do so very smoothly. The only sign of cheapness comes in the form of a too-flimsy dust cap. I also wish the Ranger came with the nice case they give you for the Pronto. The high level of mechanical quality, fortunately, is carried over to the optics. I still get a "Wow" from some Schmidt-Cassegrain users. The Ranger's optics are so sharp and contrasty, they give you a taste of what's possible in a high quality refractor. The view through one reminds me -almost- of the view through a modern Astro-Physics or Takahashi apochromat. The Ranger is surprisingly versatile. On planets, you will need a barlow, but the scope takes high magnification well; there's very little breakup in the images even at 180X (I didn't go beyond this power due to the lightweight Bogen setup.) On deep sky, the Ranger will lose out to a good 4.5" or 6" Newtonian. However, I've detected a remarkable number of extended objects with the little guy from my suburban driveway. All of the Messier galaxies in the Virgo Cluster, for example (with the possible exception of M91), are within easy reach. Coupled with high quality eyepieces, the Ranger becomes a great rich field scope. Looking at the Double Cluster in Perseus with a 13 mm Nagler, for example, is a breathtaking sight (I use the 13 mm Nagler a lot in this scope. An observing friend looking at this setup, scratches his head and says he doesn't know which end to look into.) Drawbacks? A few. Due to the limited aperture, using complicated eyepieces like Naglers tends to dim the view a bit, which is the last thing you want. And yes, there is some false color, as AP or Tak owners are constantly pointing out. However, the purple halo is a dark, subdued shade of purple, and to me relatively benign. The Ranger has less false color than the new 80 mm f/11 refractors from Celestron, for example. However, it has a bit more color than the f/15 models. Draw again, podner... After using through the Ranger, looking through the FS80WA draws two responses, more or less at the same time. 1) Images are brighter through the Celestron, somewhat surprisingly so. I expected the Ranger's ED glass and superior coatings to help make up for the 30% or so light gathering disadvantage, but 'twasnt so. I could start to see detail in extended objects like M81 and M51 through the FS80WA when conditions allowed. Through the Ranger, they tended to remain dim smudges. 2) On bright objects, chromatic aberration is REALLY obvious. Expect to see a purple halo around anything brighter than 2nd magnitude. What's worse, the hue of purple is a bright, almost lavender color that gets irritating much more quickly than the dark, subdued purple halos in the Ranger. On very bright objects like the moon, the purple color begins to look like something out of a science fiction movie. It looks as if there's a massive alien spaceship with huge purple headlights parked right behind the limb of the moon. Not subtle. I tried the supplied aperture mask, which stops the objective to around 40 mm. While a lot of the false color went away, the images became way too dim, and the scope became nearly useless on anything besides the moon. The scope's planetary performance isn't anything to write home about. While you can see Cassini's division, at least two cloud belts on Jupiter and its 4 big moons, the views were not crisp. Barlows help a little, but with only 400 mm of focal length to work with, you run out of power real fast. Also, the fast f/5 focal ratio played havoc with images near the edge of the field. Even with high quality Plossls (TeleVues and Meade 4000s) stars at the edge of the field became looong curved arcs. Also, the outer 5% or so of the field became mushy, and brown colored -- contrast this to the Ranger, where the sky remained sharp and black all the way out to the field stop. OK, you want nit-picking? You came to the right place! I noticed that the diffraction patterns on the FS80WA's star images had a little "spike" at one end. Taking out the diagonal, I saw why. The rack on the rack-and-pinion focuser is held on to the drawtube by a too-long machine screw that protrudes into the viewing area. This too-long screw has been on every Orion Short Tube and FS80WA I've ever seen. The supplied 25 mm SMA is OK and is about the same quality as Meade's MA series. However, it's not nearly as good as the TeleVue 20 mm supplied with the Ranger. The small equatorial mount is adequate, although it uses a non- standard two-bolt (metric) mounting system that limits its usefulness for your other OTAs (unless you are handy with wood working or metal working.) It's more than sturdy enough for the tiny FS80WA; in fact, I wish it were a little lighter. Using Naglers and Panoptics (which are said to be tested for sharpness by TeleVue even at f/4) dramatically improved matters. Edge of field aberrations went away, and general sharpness improved, as well. The scope's performance on deep sky approached that of the Ranger's (although the Ranger did maintain its edge on sharpness and contrast.) The problem with this is, beginners are not likely to use a $250 eyepiece in a $300 telescope (unless, of course, they grow up to be equipment reviewers.) Finally, my FS80WA has pinched optics. Pinched Optics Inexpensive refractor objectives are generally held in place by a metal locking ring. When this ring is tightened down too far, it bows the objective lens outwards slightly, resulting in pinched optics. Fortunately, pinched optics are very easy to detect. Defocus a bright star, and instead of a round circle of light, you will see a triangle. This triangle is the hallmark of pinched optics. I mention this because the Orion Short Tubes and Celestron FS80WAs I've looked through during the past year or so seem to have pinched optics in hugely disproportionate numbers. Since these opitcs are made in China, perhaps the lens maker(s) are tightening down on the objectives for fear that they might loosen on the trip overseas. In any case, it is important that you check in advance, if at all possible, to see if your version has pinched optics. It does affect stellar images, and tends to soften images on planets and the moon. In a final twist, my FS80WA shows severe pinched optics only in winter. In the summer, the locking ring must expand just enough to un-pinch the optics. Thus, mine shows great stellar images in warm weather. Weird, huh? I've just read what I've written (above), and it seems that I've been a little harsh on the little FS80WA. I should stress that this is a Real Telescope, and is capable of serious work. Mine has already given me much pleasure, and I expect it will continue to do so for some time. It is recommended, and you should consider picking one up.
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