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Orion Apex 127 Maksutov-Cassegrainian

Posted by Lawrence Carlino   05/27/2004 12:00AM

Orion Apex 127 Maksutov-Cassegrainian

The Maksutov telescope, from its brilliant 1944 design by Dimitri Maksutov through its commercial adaptation by Questar, has almost always been considered a premium-quality instrument, with prices to match. But beginning with the introduction of the Celestron 90 and the extensive Meade ETX series, improvements in optical technology and fabrication have moved these desirable scopes into the mainstream of price and availability. The Maksutov-Cassegrainian, with its long focal length, traditionally sharp optics, short tube, and light weight is a natural for observers "on the go" or with limited storage space.

The introduction of the Apex and StarMax series of Maksutov-Cass telescopes by Orion, a little over a year ago, tantalized amateurs with the hope of obtaining a premium instrument at bargain prices. These Chinese-made scopes are made to Orion's specifications and promise to deliver, with a "no frills" philosophy: quality optics, rugged construction, and value for the dollar. But do they measure up to the advertising claims?

First Impressions

Already owning a suitable equatorial mount, I ordered the Apex 127 version of the telescope, the optical tube assembly only. With the optical tube came a dovetail-mounted 6x26 erect-image finderscope, a 45 degree terrestrial diagonal, a 25mm Plossl eyepiece, visual back with photo adapter threads, and a very nicely made soft padded carrying case to accommodate the tube and related accessories. The tube itself is finished in an aesthetically pleasing deep-red metallic finish. The front cell housing the meniscus front lens and rear cell are contrasting dark gray cast aluminum. The 15" long OTA weighs only 8.6lbs. This is clearly a very attractive and well-built instrument. I mounted the optical tube on a Celestron CG-4 equatorial, a unit almost identical to the AstroView mount supplied with the StarMax version of the telescope. This proved to be a sturdy combination with both reasonably light weight and more-than-adequate damping. For those who require an even sturdier configuration, the beefy SkyView Pro equatorial is offered with either single or dual-axis drives, but at a substantially higher price.

Optical Performance

When the winter snows came to a temporary halt, I attempted to observe through some fleeting "sucker holes" in the perpetual cloud deck - and the results were both surprising and delightful. With a long f/ratio of f/12.1 and a focal length of 1540 mm, the little Apex provided some very fine views of Saturn, tight double stars, and the few deep-sky objects I was able to observe. Saturn, at a magnification of 118x with a 13mm Nagler T6 in the drawtube, was very sharp and solid. The Cassini Division was easy to spot and well defined as was the shadow of the planet on its rings. Equatorial belts and the dusky polar area on the planet's globe were nicely discernible as were moons Titan, Rhea, and Iapetus - all in spite of high-altitude cirrus that marred the view somewhat. Subtle gradations in contrast provided an image that reminded me of the view in a good 4-inch achromatic refractor, but with no false color.

Castor, a good test of telescope resolution and image quality, was quite impressive with the Apex: both major components were surrounded by clean, symmetrical first diffraction rings at powers of 118 and 171x with fainter outer rings coming and going with variations in seeing conditions. Plenty of dark sky between the stars made the split both easy and satisfying. Inside and outside of focus, stellar images were nicely symmetrical and similar, but not identical in character. Triple star Iota Cassiopeiae also resolved well, with the closer, fainter companion nestled just outside the primary star's first diffraction ring. Overall image quality, sharpness, and contrast were similar to that of my Celestron 5, a” tried-and-true” instrument of excellent quality. If anything, the little Orion scope was a touch better than the Schmidt-Cass in the contrast of planetary detail, though both scopes produced satisfyingly sharp images. Faint objects, however, were noticeably brighter in the Celestron, due most likely to its high-reflectivity coatings and slightly greater effective aperture.

Drop Test!

When Orion advertised the construction of the Apex 127 as"no compromise," an allusion to the scope's solid all-metal parts, I was content to believe them. But a sheet of ice on my driveway, covered by a sinister blanket of newly fallen snow, sent me into a free-fall with the telescope and mount crashing heavily into the blacktop. The finder scope and dovetail bracket were sheared off, as was the star diagonal, and I feared major damage to the telescope. After retrieving some tiny parts and uttering numerous internal profanities, I attempted to assess the result and salvage what I could.

Surprise! The less- than-a week-old instrument sustained some minor blemishes to the tube and cast aluminum end cells, but the finder, its bracket, and star diagonal re-attched without a problem. Optically, the scope had lost its perfect factory alignment, but three collimation screws recessed in the rear cell and adjustable with a small hex wrench made re-collimation possible in about 20 minutes. This "push-pull" arrangement was not easy to use, but it did restore exact optical alignment. Obviously, I was very pleased with the Apex's resiliant nature; a lesser telescope might well have been destroyed.


With the scope fully functional once again, I was able to catch some fleeting glimpses of the moon a bit after first quarter. The Apex revealed some sharp, high-contrast detail, including the chain of tiny coalesced craterlets near Copernicus. A few days later, the radial streaks and terraced walls of Aristarchus and "cobra head" of nearby Schroter's Valley displayed an excellent level of detail at 118 and 171x. Magnifications of 250x were handled nicely without evidence of image breakdown.

Jupiter, when it achieved reasonable altitude, was likewise impressive: the equatorial belts were clearly defined as were the polar areas, red spot hollow, and resurgent Great Red Spot. The four Galilean satellites were recognizable from their differences in size and coloration. Clearly, this telescope, though quite small, is capable of delivering some excellent lunar and planetary views. Contrast, although good, was (as one would expect) not up to the level of a quality 4-inch APO refractor such as the Borg 100ED or Takahashi FS-102. But the $399 price of the Apex puts the matter into perspective.

The Deep Sky

Although advertised as a 5-inch telescope, the Apex127 has an actual clear aperture of some 4.7", a result of the effective optical diameter of the front meniscus lens. Light throughput, however, gives the scope a touch more light grasp than my 100mm Borg ED refractor. Images in the Apex are very slightly brighter, something that manifests itself in deep-sky observing. At 51x, about the lowest power obtainable with the long-focal-length instrument, a 30mm Celestron Ultima series eyepiece provided a beautiful vista of the Orion nebula. Faint green "wings" reached out from the body of M 42, and the four stars of the Trapezium were sharply defined. Effective internal baffling in the Apex made for a dark sky background and excellent contrast

Galactic star clusters such as Auriga's M 37 and Canis Major's brilliant M 41 looked much like a fine sprinkling of star dust on a velvety backgound. M 35 in Gemini was also attractive, with its companion cluster NGC 2158 visible as a ghostly patch in the same field of view.

Galaxies were not particularly bright with the scope's modest aperture, but the relatively low-in-the-sky M 81 and M 82 did display hints of detail at medium magnifications. Again, the views were reminiscent of those with a good 4-inch refractor and, perhaps, similar instruments such as the Celestron 5 and Meade ETX 125. Although no bright globular clusters were accessible in the winter sky, I suspect that the Apex would nicely resolve the brighter ones, at least partially.

This, overall, constitutes very satisfying deep-sky performance with only one down side: the narrow low-power field-of-view of just one degree precludes full images of large objects like the Pleiades and Andromeda galaxy complex. For that purpose, a short- focus small refractor works better.


In addition to the telescope's impressive ruggedness, a few notable features add to the telescope's "better-than-expected" aura of quality. The moving-mirror focusing knob on the back plate, in the tradition of Celestron and Meade SCT's, moves with smooth precision with no detactable image shift. Feedback and effort seem just about ideal. The finderscope is attached to the main tube with a dovetail bracket and can be removed in a matter of seconds - a nice feature. Additionally, the aluminum stalk holding the finder is quite tall, allowing easy access to both main scope and finder without incurring major facial damage. The finder is aligned with an ingenious spring-loaded "x -y" two-axis set-up that makes the process quick and easy. Unfortunately, the 6x26mm erect-image finder itself is too small for astronomical use, though it does have decent optical quality. An upgrade to a red-dot pointing device or 6x30mm finder is recommended.

The Apex optical tube has a rather long aluminum bracket attached to the bottom of the scope to accommodate a variety of mounting options. Several threaded .25" and metric holes allow mounting to a sturdy photo tripod for terrestrial or low-power astronomical use, and to a number of medium-weight equatorial mounts such as the Celestron CG-4 or Orion's own AstroView.

In Summary

The maxim "you get what you pay for" almost always applies to the purchase of a telescope. But in the case of the Orion Apex 127 and its equatorially mounted brethren, I'll have to make an exception. At $399 ,this little Mak-Cass strikes me as a genuine value. With optical performance approaching that of a good (and much more expensive) 4-inch APO refractor, rugged construction, and obvious portability, it's the real deal. Just don't expect the absolute imaging perfection of a Takahashi or AstroPhysics refractor. The Orion scope’s main competition, the Celestron 5 is its approximate equivalent in capability, though it has the advantage in lighter weight ,a wider field-of-view, and (perhaps) more consistent quality control - but it does cost some $200 more as an optical tube assembly.

For astronomical observers, the StarMax 127 with its equatorial mount and included 90 degree astro star diagonal ($569) seems the best way to go. The super-heavy-duty SkyView Pro 127 ($649) adds significant weight and bulk, but it does sport a 6x30 finder and has optional dual-axis drives to permit astrophotography and ccd imaging. In any of these three configurations, the telescope is an impressive value.

One word of caution: though the quality and consistency of Orion's Chinese-built scopes continues to improve, there may be variations. A second Apex 127 that I tested had optics about 95 percent as good as mine, but it arrived with a slightly dented tube and scratches on the rear mirror cell. Fortunately, Orion's 30-day "no questions asked" return policy makes such a situation no more than an inconvenience.

Given the satisfaction I've experienced from my Apex 127, I highly recommend it where price and portability are a major consideration.

Clear Skies!
Larry Carlino

Click here for more on the Apex 127. -Ed.