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SkyQuest™ XT10 IntelliScope™ 10"/25.4cm f4.7 Dobsonian Telescope
ONE GIANT LEAP FOR DOB-KIND - EVOLVING NOVEMBER 2003! The Orion SkyQuest™ Dobsonian telescopes are designed for beginners who seek the best possible view of the faint Deep Sky objects while on a constrained budget. These telescope benefit from years of study and refinement of those Dobsonian style telescopes already on the market; they include advanced design and materials to keep them lightweight and simple to use. Furthermore, the accessories included are common sense items to insure a good first night out; these are items that would normally be optional for competing telescopes. Our simple to use Orion SkyQuest™ XT8 and XT10 telescopes always provided their owners with more bang for the buck for the dollar. And these are each backed by Orion and Company Seven - two of the most credible and competent sources of telescopes in the marketplace. While the SkyQuest™ series telescopes continued their dominance over all other economical Dobsonians worldwide by virtue of their dazzling optics and superior engineering, for 2003 we add a new contemporary lightweight base design and most exciting of all, the ability to locate any of more than 14,000 fascinating celestial objects with a nudge and some pushbutton ease! Right: Orion SkyQuest™ XT10 IntelliScope™ telescope with standard 9x 50mm Finder, 2" Focuser, Navigation Knob, 2" and 1.25" Eyepiece Holder, four vane thin profile Secondary Mirror Spider. Note the IntelliScope™ Control shown here is optional (51,107 Bytes). Click on image to see enlarged view (85,940 bytes)
Radical Resolution AND The Industry's Best 10 Inch Dob Just Got 14,000 Times BetterLight Gathering Power! The XT10's 48 inch (1,200mm) focal length (f4.7 focal ratio) helps to keep the telescope manageable and portable, and yet it will still provide good high as well as low magnification observing. The XT10 is our most popular Dobsonian Reflector among those who desire a manageable telescope with the light gathering and fields of view potential for the observing many of the most popular deep sky objects. With about 920X the light gathering power of the unaided eye, the XT10 telescope provides an increase of about 1.55X over the light gathering power of the better 8" Dobsonian models. Keep it in mind however, the XT10 is a big telescope for big celestial appetites! Before you buy a telescope such as this, consider carefully its overall size and weight before you buy. You may be better served to buy it's smaller cousin the Orion SkyQuest™ XT8 IntelliScope™. Of course those with serious photon appetites may choose to buy it's even larger cousin the Orion SkyQuest™ XT12 IntelliScope™!
Adjustable 2" Focuser Another feature of the XT10 over most other competing and smaller Dobsonian models is the standard smooth 2" focuser. This aluminum focuser accepts low magnification, wide field of view 2" eyepieces as well as the common 1.25" diameter eyepieces. The Focuser Base Plate incorporates user adjustable set screws to facilitate collimation (aligning the optical path) of the telescope. And with an optional high quality low magnification eyepiece, one could reach 23X observing areas as large as 2.1 degrees across! Keep in mind that at such a low magnification the Exit Pupil (the diameter of the cone of light coming out of the eyepiece) is 11.13mm and so this may not be as good a choice as using an eyepiece that provides 36X showing 1.77 degrees with a 7.08mm Exit Pupil. If this telescope were equipped only with a 1.25" focuser, then the maximum Field of View would be only 1.23 degrees at 31X - but with 8.1mm Exit Pupil; a more practical 32mm eyepiece would provide 1.23 degrees at 39X with a more practical 6.48mm Exit Pupil. The factors of aperture and the 2" focuser are particularly important to people who seek better views of the extended, faint deep sky objects (nebulae, star clusters, galaxies, comets, etc.). In effect the stellar magnitude reach is extended from about 13.8 of an 8" telescope to about 14.3. And still this telescope affords the contrast and clarity qualities required to observe the moon, and planets; the XT10 actually can reveals changes through out the observing season! With a comparatively small central obstruction, and fewer optical surfaces, the contrast and brightness can actually surpass more expensive designs such as some 8" and 10" Schmidt-Cassegrain telescopes.
What characterizes a Newtonian reflecting telescope?: The optical arrangement of this Orion optical tube assembly (OTA) is known as a "Newtonian". While an English mathematician originated this optical concept, it was Sir Isaac Newton who first made a working model in 1668, and he continued refining the design well into at least 1671. The larger of the two is a Parabolic "Primary" mirror, this is the factor by which most telescopes are described; hence an 10" telescope has a primary mirror of 10 inch (25cm) in diameter.
The Primary mirror of the telescope is precisely mounted in a Cell at the rear of the telescope. The light entering the telescope is gathered and then reflects forward in a converging beam, to the Secondary Mirror (an elliptical flat) that is positioned near the front of the telescope and tilted at a 45 degree angle. The light from the Primary Mirror is reflected by the Secondary out to the side of the telescope and through the Focuser to form a virtual image at a point beyond the focuser. An eyepiece to enlarge the image for viewing, or a camera for photography is placed on the focuser to view or capture the image.
In a departure from most imported reflecting telescopes, the Primary Mirror of the XT10 is made of Pyrex®. The American firm Corning Incorporated developed Pyrex® a well proven material which has been marketed since 1915. Pyrex® is a sophisticated borosilicate glass composition made of Silicon, Boron, Sodium and Aluminum. It provides good chemical, thermal, mechanical and optical properties. Its density (g/cm3) is 2.23. This material can be polished to provide and hold a high quality of view, and provides stability and optical performance better than mirrors in most telescopes sold anywhere near this price range. Continuing its tradition of innovation and product improvement, Orion chose to make the change from Borosilicate crown glass to Pyrex® in October 2002. The Mirror is made in China and by 2002 we became aware of how the rapid pace of modernization of industry in China was providing suppliers who could quite consistently churn out good optics at modest prices. Of course, if you wish to pay a little less then the factory can spend less time in polishing or figuring the optics or trim some cost of elsewhere. And so the same factory may manufacture a telescope that appears similar for one buyer while making it to a better specification for another. We have been quite pleased with how Orion has used its influence to engineer trendsetting products, and then have them made to a very good spec. Among the considerations of a reflecting telescope is that the mirrors be precisely positioned within the OTA in terms of centering, tilt, and spacing. The overall alignment ("collimation") of the one optical element to the other, and their placing the focal plane (the point where the image comes to focus) at the correct position beyond the focuser are critical. The optical axis of the telescope should be closely parallel to the mechanical axis of the tube assembly too. Company Seven chose Orion's SkyQuest™ telescopes in part because of their consistently good quality mechanical components and assembly at the factory that facilitate collimating these telescopes precisely upon delivery, if needed.
The XT10 Primary Mirror is marked in the center with an indicator, and the 2" Focuser Base is adjustable to facilitate collimation by even the most inexperienced persons! Incidentally, since the Center Spot is located at the center of the Primary in an area obstructed by the Secondary Mirror, this mark has no adverse impact on the optical performance.
A well made reflecting telescope can offer the best view per the dollar of the faint, deep sky objects where light gathering power is essential. Light gathering power increases are more important and come quicker than one may think; consider that a 6"f8 - a 48" (122cm) long reflecting telescope may show objects about 335X fainter than the unaided eye, while the XT10 (with similar physical length) provides about 920X the light gathering power over the unaided human eye - in astronomy size can matter! The Dobsonian telescope: The characteristic simple to use Alt-Azimuth mounting, use of a lightweight primary mirror and modestly priced components evolved in the 1970's with San Francisco sidewalk astronomer John Dobson. His goal was to get the most telescope possible into the hands of the amateur observer for the lowest relative cost. This arrangement has become known as the "Dobsonian" or "Dob". The Dobsonian telescope consists of an optical tube assembly riding on a wooden alt-azimuth platform. The optical tube may be made of tube up to 18 or 20 inches in diameter. These tubes are typically made of Sonotube/cardboard, or plastic, or rolled metal. The Orion XT telescopes employ a rolled steel enameled tube finished internally in an anti reflection paint, with the exterior in a contemporary deep bronze metallic enamel. This tube holds optical collimation well even with temperature or humidity changes. This thin wall tube permits the designer to select a smaller secondary mirror/obstruction. And this keeps the tube lighter weight and more compact than heavier Sonotube tubes. In the case of the better made larger Dobson telescopes (12-1/2 inch and larger), a Truss arrangement is employed in order to facilitate disassembly into a more manageable and compact package. Our best-made Dobson telescopes up to 10 inch aperture are those offered by Orion. While our larger Dobson telescopes include the Truss tube telescopes made by Astro-Systems. Working with Gravity: The center of gravity lies directly over the center of rotation in both directions, so no matter to where the telescope is pointed, the weight is evenly distributed through the mount to the ground. This characteristic, and sound design results in almost complete elimination of unwanted vibration and oscillation; the inevitable downfall of many poor telescope mounts. Whereas in many economical telescopes the image seems to bounce around forever after the scope has been touched, this is not the case with well made Dobsonians. In addition to getting some help from Newton's Law, Orion engineers developed and now refined the original CorrecTension Friction Optimization system. This new system is a mechanism to adjust the tension or drag on the altitude bearings to compensate for varying loads of eyepieces, cameras, finders, etc. Bearings molded from ultra-high molecular weight (UHMW) polyethylene and Teflon provide silky smooth motion of the telescope on both axes. Orion's engineers not only streamlined the rock-stable Dobsonian base, but they also provided a lighter weight contemporary structure to the Base Side Arms.
Right: XT8 IntelliScope™ pointing to M5 Star Cluster by Bob Fuller, M8 Nebula by Coombs, and M33 Galaxy by Lorenzi. (127,639 bytes). Click on image to see enlarged view (268,752 bytes). The IntelliScope™ system is an advanced form of digital setting circle providing a digital readout of position, with information about celestial objects in the database. This system features an electronic position indicator (Encoder) which is affixed to each of both axes of the telescope Base (or Carriage). The Azimuth (left-right) motion Encoder is provided with each Intelliscope Base when you buy the telescope. As you assemble the Base you may install the Azimuth Encoder, or if you pick up the telescope at Company Seven then you may have the instrument assembled with the Encoder(s) already installed for you. To activate the full benefits of these "digital setting circles" all one needs to do is buy the optional IntelliScope™ Computer Controller, install the provided Elevation (up-down) Encoder onto the Base, plug in the IntelliScopeª Computer Controller, and go! Left: IntelliScope™ Control with Cable (32,298 bytes). Click on image to see enlarged view (56,680 bytes).
When the IntelliScope™ series telescopes were introduced in 2003 the IntelliScope™ Computer Control system was an option, so the telescope could have been ordered with or without this system. But since virtually everybody who buys these telescopes wanted the IntelliScope™ control and encoder system, the
Full IntelliScope™ object-location functionality can be added at any time with purchase of the optional plug-in Controller.
The XT10 Base includes a convenient Eyepiece Accessory Tray. This standard eyepiece holder is provided with slots for up to three 1.25 inch accessories, and one of 2" diameter. Furthermore, this tray is held in place by two keyhole shaped screw holes so that customers may easily slide the tray up and out to remove the tray for transport or if desired. To keep dew or other contaminants from marring eyepieces set on this tray Company Seven suggests you keep eyepiece caps in place and consider the use of dew prevention devices including our Kendrick heaters.
And if you tire of holding the lightweight controller, you can holster it and take a break with the optional Holster!
A Hands-On Telescope: The Dobsonian is a telescope you can push around - literally. You point it by simply nudging the tube up or down, and left or right by hand. Trunnions on the tube rotate on 5 inch diameter low-friction plastic bearings, allowing the telescope optical tube assembly to move up and down (altitude). The Base rotates horizontally (azimuth) around a center pivot. The motion on both axes is "buttery smooth," letting you guide the scope with just the lightest touch from one part of the sky to another. You do not need to loosen and tighten clamps when targeting objects, as you must with other mounts. Dobsonians are not equatorially mounted and so they are generally moved only by hand. While it is possible to add motors and computer control (to automatically find and track stars) it is generally not necessary or cost effective on smaller Dobsonians. Some companies do sell Dobs complete with tracking systems however, even these factory made tracking Dobsonians are not completely satisfactory for deep-sky astrophotography.
The Dobson design remains the first choice among serious deep sky observers, and it is not uncommon to find custom or home made 8" to 36" aperture "Dobs" in use at dark sky observing sites around the world.
The Orion SkyQuest™ Dobsonian telescopes sold by Company Seven in the 6" to 10" apertures provide excellent affordability and simplicity of operation, this makes these Dobsonians a great first telescope for entry into the hobby of amateur astronomy. Larger Dobs, though bulkier to transport and often requiring a step stool or ladder to reach the eyepiece, remain highly popular among experienced observers. Compared to similar-aperture Newtonians on their heavy equatorial mounts (and at times awkward eyepiece position), Dobsonians are delightfully economical. Experienced amateurs often claim that the best combination of portable telescopes for most persons pursuing astronomy would be an 18" to 20" Dobson, with a 6" Apochromatic Refractor!
Noteworthy features of the SkyQuest™ XT10 include:
Innovative Design!
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"Starry Night Special Edition" is a basic version of the more capable "Starry Night" version 5.0 astronomy software series; this software will help you learn the night sky, see what is up day or night, now or in past millennia, plan your observing sessions, and print out charts and information about the celestial wonders. The set also includes "SkyTheatre", a DVD by Imaginova so your television or PC becomes a spaceship on a voyage through our Solar System. The set is compatible with both Macintosh computers running OSX version 10.3 or later, and with Windows XP for PC. Your personal planetarium and guide to the night sky!
Left: CD-ROM "Starry Night Special Edition" with bonus "SkyTheatre" DVD suite (43,322 bytes).
XT10 10"f Telescope Specifications:
FURTHER READINGTo read additional information about the Orion SkyQuest™ Intelliscopes sold by Company Seven feel free to download the Orion SkyQuest™ Intelliscope Telescope Instruction Manual. This is the complete 20 page illustrated instruction manual as furnished with our Orion SkyQuest™ XT6, Orion SkyQuest™ XT8, and
COMPANY SEVEN'S ASSEMBLY & TESTING SERVICE:All of the information we provide on line and by phone or E-Mail to the customer, our expertise, our unrivaled showroom and museum (an increasing rare sight), and the fact that one may buy the basic instrument from us or elsewhere at about the same cost should be enough to persuade one to choose Company Seven. However, we do even better, we make it in your interest to buy from us.Orion has been quite good at making the factories overseas produce a great value. But once in a while something less than perfect slips by; a part is not glued just right, something is installed a bit off, or a component is damaged in transit. If you receive one of these telescopes and if you know enough to recognize an anomaly then it is a simple matter to call Orion or Company Seven for a prompt exchange or replacement parts. We both have very good reputations for after sale support and a money back guarantee.
When we assemble the XT we evaluate cosmetics, often cleaning off surplus glue or dirt. We install the Primary Mirror making those first and most time consuming adjustments to assure each optical and mechanical component is nominally installed. We are happy to provide you with the optional tools to collimate a telescope when it becomes necessary (after all some years from now you will probably want to pull the mirror for cleaning) and more importantly we will teach you how best to proceed. As we have worked on so many of these instruments we have developed a good sense of how a properly made and adjusted Focuser should feel. We know the tricks to make the telescope move smoother up and down, left and right. We know how to make it last longer - in fact we change out some components with superior alternatives. There are a few techniques we have devised along the way to improve reliability when we install the optional IntelliScope™ Controller and Encoders. We find the quality control problems however, while we do not expect a "Rolls Royce" fit and finish on the XT telescopes, we work so that the telescope will perform as well as experience shows it can. And as we process the telescope we perform some tests that will reveal to our experienced eye whether or not the optics were made and collimated as they could be. And finally, we generate additional information that is provided to the owner; this will characterize the potential of the telescope for visual applications, and with an optional Equatorial Mount what the XT may accomplish photographically. One will never read a sad tale from someone who actually bought their IntelliScope™ at Company Seven. We invite you to attend a Star Watch activity of any regional astronomy club and compare a telescope that bears the Company Seven acceptance label with those from elsewhere. In fact more and more we hear accounts of people at such events who bought their "Orion XT clone" elsewhere being convinced it was a great value until they felt the motion of our telescopes and gazed through the eyepieces we recommended. Company Seven's customers tend to progress further in the hobby than others. This is in part because we are helping them as we wish someone else would have helped us. We are not archetypical salesmen, instead we are experts who can teach you about the instruments and provide the sincere good counsel.
SUGGESTED ACCESSORIESThese are optional accessories that are not included with the telescopes that we highly recommend for your viewing pleasure and long term success:
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