Telescope Reviews, Page 2

Telescope Reviews, Page 2

By Ed Ting Updated 1/28/00

Click on a scope below: 1) Meade 10" LX50 Schmidt Cassegrain 2) Celestron C 4.5 Reflector 3) Brandon 80 mm Master Birder Spotting Scope (Brief Impression) 4) Orion Deep Space Explorer 16" Dobsonian 5) Orion (U.K) Europa 8" f/4 Schmidt-Newtonian 6) Vixen 60 mm f/15 refractor 7) Saturn by Meade 60 mm f/15 refractor 8) Meade ETX
1) Meade 10" LX50 Schmidt Cassegrain (10" f/10 Schmidt Cassegrain, LX50, 25 mm MA, $1695, tripod, $295) (LX200 version, GOTO computer, 26 mm Plossl, $3195 complete) Recently, three of us agreed to meet at 4 AM in this open field out in the country, with the intent of catching Mercury in the pre-dawn light. The whole endeavor turned into a kind of "Waiting for Godot"-like experience; the planet never did materialize, but in the meantime I did get to play with one of these units. If you are torn between buying the 8" and 10" versions of this scope, you should know that the 10" is MUCH larger than the 8". The increase in weight is only 25%, but the bulk differential is closer to +50%-75%. It can take a person twice as long to set up the 10", as opposed to the 8". That aside, this is one fine scope. The sample I saw had rather seriously undercorrected optics. Inside of focus, there was no airy disk at all, just one giant, bright 1st diffraction ring. Outside of focus, the rings were spread around more conventionally. In practice, though, such things rarely matter, as was the case here. The views were fine. M13 was completely resolved to the core, and was a breathtaking sight with a 13 mm Nagler. The Ring Nebula was also impres- sive, although no central star was present due to the almost-full Moon. Epsilon Bootes was cleanly split (although seemingly no more so than on my 4" Takahashi.) Fans of large deep sky objects may feel a little boxed in with this scope's narrow field of view (the focal length is 2500 mm). In short, a good alternative to an 8" S-C, provided you are willing to lug it around, at a reasonable price (LX50 version). 2) Celestron C 4.5 Reflector (4.5" f/7.9 Equatorial Newtonian, 6X30 finder, 26 mm Plossl, $599)
C 4.5 Celestron's C 4.5: A great tool for introducing yourself to astronomy
What a great starter scope! The C 4.5 makes a surprisingly good planetary instrument. Saturn shows up as a large pastel-colored ball, and Cassini's division is clearly visible. Three moons were seen on one side of the rings. While impressive, the 4" Takahashi nearby spotted 4 moons, and the Tak's star images came to much sharper pinpoints. These things are to be expected, of course, in a scope costing 4 times as much! The version I saw had very good optics, with only slight undercorrection, and took high magnification well. At one point we had a 9 mm Nagler atop a TeleVue 3X barlow. While the setup looked rather ridiculous, the image was only just beginning to break down. On deep sky, the little 4.5 performs quite well. However, when set side by side with my 6" reflector, the larger instrument delves deeper into the star fields around objects like M81/M82 (this is to be expected, of course.) There is some competition. Meade's 4500 is a popular alternative, and is priced at only $399. However, the 4500's mount is shaky, and nowhere near the quality of the Vixen Polaris mount supplied with the C 4.5 (Note, however, that the Polaris and Super/Great Polaris are NOT the same! The Polaris has a lighter equatorial head, and no extendable legs.) I have not seen the Orion Sky View ($399), so I can't offer any comment on it. A very good scope at a reasonable price, and a pleasant surprise. Update, 3/29/98: Celestron has now discontinued this model. It's been replaced by the less expensive C114HD. I find the HD mounts to be far less substantial and smooth than the Polaris mounts of old. Try to use one before purchasing. 3) Brandon 80 mm Master Birder Spotting Scope (Brief Impression) (80 mm f/5.6 triplet apochromat, 2" 45 degree Amici prism, 30 mm eyepiece, $995)
Brandon 80 mm
I had a chance to look through one of these for a few minutes under very dark skies recently. The scope is sold as an OTA only with a 1/4" thread socket at the bottom. The case is coated in a contoured rubber armour. It comes with a 45 degree Amici prism. Although extremely well-made, the prism drove me nuts. It also cuts off some of the light passing through it (if you look through the objective, you see a stop-sign like pattern in the circle of light). I am told that some dealers will substitute a 90 degree diagonal at no charge. Check before purchasing. In Brandon's literature, there is no mention at all about astronomy; it's sold as a birding scope. They do have another f/6 astronomical version, which I'm told is even better. The Birder isn't recommended for use above 48X. This scope had almost perfect optics. Diffraction ring patterns showed almost no spherical aberration. Also, there was virtually no false color around Sirius. During casual use, the scope produced sharp, typically refractor-like images. And the big 2" Brandon eyepiece is about as good as it gets. The owner of this scope thought he could detect some astigmatism towards the edges, but I couldn't see it. There will be an issue as to whether or not you should buy a TeleVue Pronto instead. Both scopes are about the same price and are comparably equipped. You cannot go wrong with either one. The Brandon has the advantage of a larger objective (the extra 10mm means a lot at this level) and the eyepiece is even better than the excellent TeleVue 20 mm Plossl supplied with the Pronto. The Brandon also has a nicer (leather) case. On the other side, the Pronto has better build quality (it feels as if it were carved out of a solid bar of iron) and a smoother focuser. You also get a 2" to 1.25" adapter and a 90 degree diagonal as standard. The Pronto's objective, however, does show false color. My Ranger, which shares the same objective lens with the Pronto, has some minor under-correction. 4) Orion Deep Space Explorer 16" f/4.5 Dobsonian (16" Dobsonian Reflector, f/4.5, 8X50 finder, 26 mm Sirius Plossl, $1369-$1469)
16 inch Dob The Big One: Orion's giant 16" Dobsonian
Our club has one of these as their "club scopes", although it is finding a permanent home in a soon-to-be-built observatory. At this level of aperture, familiar objects in the sky stop being subtle, fuzzy patches -- they take on real definition and detail, just like the photos you're used to seeing in magazines. The optics in this scope are remarkably good, considering the f/4.5 focal ratio. The Sirius Plossl supplied has good light throughput and respectable sharpness across its field. It reminds me of the Meade Series 3000 Plossls, which is high praise. This "light bucket" takes some getting used to, if you're not accustomed to large- aperture instruments. While looking for M81/M82 for example, I accidently found another faint galaxy (probably NGC 2976 or 3077), and was taken aback. I thought I knew the star field around M81/M82 quite well, and had never seen another galaxy in the area before (P.S. Now I know the area much better, after some study!) M31 shows its dark band prominently across the entire field of the 26 mm Sirius, and M74 -one of the most notoriously difficult Messier objects -- is easy under dark skies. Disadvantages? Well, the obvious: size and weight. At 175 lbs, this is a two-man scope. The optical tube alone weighs 95 lbs and is tremendously cumbersome to boot. Also, while looking near the zenith, you will need a small step stool to get to the eyepiece. You may need a small ladder if you're working with kids. And at certain positions, you will practically have to climb on the tube to get to the finder - not very dignified! All in all, a great choice for a big light bucket, provided you have the means and desire to lug it around night after night. 5) Orion (U.K) Europa 8" f/4 Schmidt Newtonian (8" f/4 Schmidt-Newtonian, OTA only, 25 mm Plossl eyepiece, finder, $1150)
Schmidt-Newt
Now here's a scope for that special astronomer on your list who has everything! I'm told there's only one of these in the country right now, and I've seen it. These British scopes may or may not be available in the US at this writing. If you're not familiar with the design, a Schmidt-Newtonian is just like a conventional Newtonian reflector, except that it has a Schmidt corrector plate on the front. If you didn't look at the front of the tube, you'd think it was a normal Newtonian. A conventional Newtonian operating at f/4 would have intolerable off-axis aberrations. The addition of the Schmidt corrector plate reduces edge of field coma and astigmatism by about 40%. Thus, an f/4 Schmidt-Newtonian will exhibit aberrations similar to a conventional Newtonian operating at f/5.6 or even f/6. On the downside, a Schmidt-Newtonian requires the light to pass through an additional (non-linear) element, and a dew-collecting one, at that. We tried the Europa 8" f/4 on the supplied equatorial mount and once again found that this mount is inadequate for such a large load. Also, if you intend to manually track in RA, you'll have to contend with the angry, flesh- ripping brass gear that serves as the RA knob. Unfortunately, the RA motor induces a 2 arc-second vibration that makes splitting close doubles nearly impossible. And speaking of that mount, it turns out to be just fine for small refractors. I bought one myself. I just think it's a little light for an 8" reflector. If you have a Super/Great Polaris and some 8" mounting rings, however, you'll be all set. The scope is quite pleasing as a rich-field instrument. Large objects like M35, M42, M31, and the Pleiades are nicely framed at low power, and the generous aperture really brings in the light. I noticed some aberrations about 10%-15% away from the edge of the field. And in the last 5% or so of the FOV, coma and astigmatism increase rapidly. Stars become long, curved lines. The star test was a bit of a mess. The diffraction rings showed up moderate undercorrection and some zonal error. The scope was slightly mis-collimated as well, although I should note that at f/4, it does not take much mis- alignment to throw off the whole optical train. We found that using good eyepieces (like Naglers) dramatically improved the situation. Curvature of field only occurred very near the edges. Otherwise, this scope is going to be very unforgiving on your cheap Kellners or Orthos. We didn't have any Panoptics handy, but we suspect they would work well. The Europa has plenty of...well, plenty of "character", or "quirks", depending on your point of view. Examples: The right angle finder's eyepiece does not have conventional crosshairs; rather, there's a cheesy piece of thin metal inside, like the pointer on a compass. You use the metal strip to center the object in the finder. The problem is, the pointer cuts off a rather large part of your FOV. Also, there are no instructions or literature of any kind. And the cheap wing nuts that collimate the mirror are attached to a huge, heat-hoarding metal plate at the rear of the scope. Am I nit- picking? Perhaps, but keep in mind you're spending $1150 for an OTA. To be fair, however, any buyer of this telescope will probably own several other scopes. Instructions won't really be necessary for such person. The questionable finder and other cheap hardware will probably get replaced in short order. These comments should be taken in the proper context. The 8" f/4 Europa is a well- executed example of an interesting telescope design that is all too infrequently used. Further thoughts, 3/2/98: It's a good scope, and useful for finding dim galaxies due to its wide field. The maddening finder has been replaced with an 8X50 Meade unit. The Europa seems unusually sensitive to sky glow, perhaps due to the large corrector plate in front -- forget about finding dim objects on the horizon from your suburban skies! Also, you should plan on using a dew shield at all times. With these caveats in mind, the Europa should serve its owner well as an all-purpose instrument. Update, 4/7/99: I eventually bought this scope from its original owner. Update, 12/99: According to Barry at Orion (UK) Optics, Orion telescopes will be shipping with a sturdier mount starting January, 2000. This is welcome news. 6) Vixen 60 mm f/15 refractor (60 mm f/15 doublet achromat refractor, OTA only, $169, NLA?)
60 mm Vixen
This scope is available under a number of "aliases," using both the Celestron and Vixen names. I bought my version to use as a guidescope (the seller gave me a nice set of giant 6-point rings), but the 'lil Vix turns out to be a surprisingly fine telescope in its own right. Mounting the OTA is a hassle - no one seems to make 60 mm mounting rings anymore - but I eventually got it rigged to a Polaris mount. Spherical and chromatic aberrations were very well corrected, much better than I'd expected. The focuser is extremely smooth. The scope gave very good views of Saturn, M41, and M42. Gamma Aries was a pleasing split. I often wonder if a 60 mm refractor is "enough" for a serious astronomer. As much as I like the Vixen, my answer would still be no. The images are a little on the "dim" side. However, there is nothing wrong with it as a second scope (er, let's see...a fourth scope, in my case.) The Vixen is just too good for finder/guidescope duty. I'll probably set it up in the living room with a Quik Point and a small equatorial mount, and use it for quick peeks. Update, 3/29/98: I've done just that. It's a useful scope, more so than you might think. Here's some of what I've been able to see with the little guy: M81/M82, M65/M66, M51, M104. There was no detail of course, but I'm impressed, just the same. Most cheap 60 mm refractors throw up an annoying halo around dim stars, making them look like small galaxies. The Vixen isn't immune to this. The scope is just barely adequate for deep sky, but it seems to work well enough on planets and double stars. 7) Saturn by Meade 60 mm f/15 refractor (60 mm f/15 achromat, finder, 25 mm, 12 mm eyepieces, equatorial mount, $249) Like many in this hobby, I have railed against "department store" refractors like this one. However, I admit, I had not seen one in a while. Had they gotten better? Also, would the presence of the Meade nameplate mean that this unit was a cut above the Tasco, Bushnell etc, products? I was eager to find out. I saw this scope at a star party. The owner asked me to help her find Saturn. She admitted knowing very little, having just bought the scope for her kids. I began playing with it and soon started having trouble myself. The finder would not focus, was plagued by sky glow, and was far too dim to be of any use, so I gave up on it and began sighting along the tube. Once I found the planet, the view was fuzzy, ill-defined, and above all, dim. Very dim. The image was far dimmer than my 60 mm Vixen (above), which I'd just used the night before. The 25mm eyepiece had a tiny lens and poor eye relief; I thought I was using something closer to a 9mm. Also, the view on one side was partially blacked out, indicating that one or more elements in the optical path were not fully squared-on. Next, we tried the Orion Nebula. Two of us couldn't find it, despite having seen it hundreds of times before. Finally, I stumbled across it by accident while sweeping the area. Even then, I did a double-take. I made out one or two stars in the Trapezium, with maybe a hint of nebulosity using averted vision. The image was so dim, it was a relief to look away from the eyepiece. The equatorial mount looked similar to the $139 model sold by Orion. While not rock- steady, it was adequate and worked reasonably well. Indeed, the mount was the best part of the scope. Perhaps with different optics, the unit might become acceptable. Approach with extreme caution, and audition carefully before buying. 8) Meade ETX/ ETX-90EC (90 mm Maksutov-Cassegrain, 8X21 CI finder, RA drive, 26 mm Plossl, $595+$20 shipping)
ETX
"That thing is ssoooo cute!!" Wherever the ETX goes, this comment is not far behind. To see one, even in a magazine ad, is to want one. Meade is to be congratulated for creating such an exciting, desirable package. What's more, the ETX would seem like just the ticket for those astronomers (myself included) who have lusted for a Questar but can't afford one. I bought mine used, in excellent condition. After opening up the carton and installing the finder and eyepiece, I did what I think most people do when they first get their ETX: I set it on the kitchen table and just admired it, for almost an hour. The thing is just beautiful. On the Cool Scale it rates a "10". Unfortunately for the ETX, I then began to use it. Despite very good optics (at least on mine), there are a number of problems. 1) Your First Problem: "The Astroscan Conundrum". Where are you going to put it? You can't set it on the ground. Users wind up putting their ETXs on small tables, rolling carts, medium-duty tripods, or, in a pinch, the hoods of their cars. All of these will work, of course, but all of them negate the primary reason for buying the ETX in the first place: portability. If I'm going to lug stuff around, I'll use a bigger scope. 2) The Flip Mirror. Rotating the aluminum levers on the back of the scope inserts a mirror diagonal into the light path. Alas, the mirror never seems to return to the exact same location each time I use it. The position of the mirror has a large effect on the quality of the image (we're talking fractions of a millimeter.) 3) The Clock Drive. When you lock the RA, the clock drive can take up to a minute to engage (if it does so at all; I've seen broken ones.) By then the object will have drifted across the FOV (and sometimes out of it), requiring you to re-center the object, lock the RA, and wait again. Can you say "Catch-22?" 4) Is That Supposed To Be The Finder? Mounted atop the ETX's OTA is a tiny, round sight tube, about the size of the supplied 26 mm Plossl eyepiece. This "finder" has such a dubious reputation that an energetic modification aftermarket has already developed. I can think of at least five major criticisms: a) The aperture (21 mm) is much too small. b) The magnification (8X) is too high. c) It's mounted so close to the scope that you cannot use it within 30 degrees or so from the celestial pole without breaking your neck. d) As a result of c), above, precise polar alignment is impossible. e) The image-erecting roof prisms steal from the already-meager light supply. What's really cruel about this is that with a scope operating at f/13.8, you really NEED a good finder. It was maddening to try and locate anything unless it was near the horizon. Perhaps it would make a good planetary scope (I'll report back when I can see some), but observing deep-sky with the ETX near the pole is like trying to ride a bicycle with one foot. Astronomers are an ingenious lot, however. Most long-term ETX users I know install one of the right-angle kits on their finders, making it just passable. Better figure on getting one. I've seen compasses mounted to the drive base to help with polar alignment. And there's the add-ons from JMI to help you out. All of this, of course, costs money. I am occassionally asked by readers whether they should buy an ETX or a TeleVue Ranger. The answer, of course, depends on the individual's needs, wants, and ability. I know of some very happy ETX owners. Both scopes have excellent optics. For me, however, there's no contest. The Ranger is simple, rugged, and convenient. The ETX is none of these things. Update: 4/29/98. I've used my ETX a number of times now. Familiarity with a new device usually helps the user cope with its quirks. Unfortunately, I have only added to my list of complaints: 5) The controls are so tiny and inconveniently placed that you cannot operate the scope in cold weather with gloves on. 6) The friction on the RA and Declination axes are so rough and inconsistent that panning around the sky is a jerky exercise in frustration. I tossed the 3 spindly little legs and usually use the scope perched at the edge of a small table. This has partially remedied my minor case of "ETX-neck." The central obstruction on my unit is off center by about 15%-20%; otherwise, the optics look decent. I tested the ETX side by side with my Ranger on M35 and the Virgo Cluster. Both scopes went just as "deep" in magnitude, although the ETX was more awkward and time-consuming to use. It keeps getting in my way. I like all 5 of my telescopes, but I have to admit, the ETX would be my last choice to take out observing on any given evening. I cannot escape the thought that this product was engineered for looks (to which end it has succeeded superbly) instead of serious amateur use. Second Update, 5/29/98 Readers have noted to me that my negative reaction to the ETX is based primarily on its mechanics. As such, I removed the ETX's OTA from the fork arms and mounted the scope Alt-Az on my Bogen tripod. Unfortunately, things have not gotten any better. Now that I can directly compare the ETX's optics to the Ranger and the FS80WA, the little Mak comes up short on resolution and contrast. Its lack of chromatic aberration made its views on bright objects a little more pleasing than on the FS80WA, though. The ETX is just terrible on deep sky. I got so frustrated at its dim views that I terminated my test that night. I have tried my best to accomodate this nice looking scope, but its inconvenient design has run my patience to the limit. I have decided to move on. Update: Meade has replaced this unit with the ETX90-EC, with Autostar Goto controller and numerours small changes and upgrades. I like the newer units a lot better since they free you from having to use the finder and the stiff axis motions. End Reviews, Page 2 Back to Home Page