SkyQuest™ XT12 IntelliScope™ 12"/305mm f4.9 Dobsonian Telescope

The product line developed by Orion that came to dominate this area of the market,
introducing many amateurs to their first glimpses of the deep sky wonders!

OUTRAGEOUSLY CONVENIENT APERTURE, SOPHISTICATED SIMPLICITY - Introduced July 2004

The Orion SkyQuest™ Dobsonian telescopes are designed for the beginning to intermediate amateur 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 Orion Orion SkyQuest™ XT-6, XT-8, and XT-10 Intelliscope series Dobsonian telescopes always provided you with more bang for the buck, backed by Orion and Company Seven - two of the most credible and competent sources of telescopes in the marketplace. Now the new SkyQuest XT12 IntelliScope™ continues the trend with its dominance over all other economical 12" Dobsonians worldwide by virtue of its dazzling optics and superior engineering incorporating a new contemporary lightweight base design, with a new nine point Floatation Cell Primary Mirror Cell, 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! The XT12 can be a logical step up for those who already own smaller telescopes, or it may be a more handy second telescope - a "portable light bucket" for those with even larger telescopes.

With 1500X the light gathering power of the unaided human eye - you will know when you are on target!

Right: Orion SkyQuest™ XT12 IntelliScope™ Telescope with standard 9x 50mm Finder, 2" Focuser, Navigation Knob, 2" and 1.25" Eyepiece Holder.
Note the IntelliScope™ Control and Holster shown on the Base Fork Tine are optional (45,302 Bytes).
Click on the image to see enlarged view (68,924 bytes)

Light Gathering Power! The XT12's 59 inch (1,500mm) focal length (f4.9 focal ratio) helps to keep the telescope within the dimensional limits that most adults will find to be manageable and portable, and yet it will still provide good high as well as low magnification observing.

The XT10 has become our most popular Dobsonian telescope among those who desire an economical, manageable telescope with the light gathering and fields of view for observing many of the most popular deep sky objects. With about 900X the light gathering power of the unaided eye, the XT10 telescope provides an increase of about 1.5X over the light gathering power of the better 8" Dobsonian models. The XT12 provides a step up from the XT10 with about 1500X the light gathering power of the unaided human eye transmitted through the system, and a proportionate increase in resolving power to see finer detail. At f4.9 the telescope is a bit more tolerant of various eyepiece designs, and yet the central obstruction can be kept moderate to improve clarity and contrast when observing at high magnifications. Keep it in mind however, the XT12 is a big telescope for those with big celestial appetites! Before you buy a telescope such as this, consider carefully its overall size and weight before you buy; at first glance it does not seem all that much bigger than the XT10 however, you will need a Sport Utility vehicle, minivan or station wagon to transport it with other passengers. Or, when traveling alone then you may be able to carry the OTA in a sedan with the front passenger seat folded back; the base going in the back seat behind the driver. If you can not manage its heft, then you may be better served to buy it's smaller cousin the Orion XT10 Dobsonian telescope since its 47.5 inch (121cm) OTA length is accommodated across the back seat of most cars.

Right: Orion XT-10 (black OTA) close up showing current model 2" Focuser, with 2" to 1.25" reducer as provided with the XT12 (23,649 bytes).
Click on image to see enlarged view (84,638 bytes).

Adjustable 2" Focuser Another nice feature of the XT12 is the 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 27X observing areas as large as 1.76 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 11.2mm and so this may not be as practical a choice for those hunting the most faint objects as another eyepiece that provides 43X showing 1.5 degrees with a 7mm Exit Pupil. If this telescope were equipped only with a 1.25" focuser, then the maximum Field of View would be only 1.05 degrees at 38X - but with 8.1mm Exit Pupil; a more practical 32mm eyepiece would provide 1 degree at 47X with a more practical 6.5mm Exit Pupil.

The factors of aperture and the 2" diameter focuser are particularly important attributes for those people who seek better views of the extended, faint deep sky objects (nebulae, star clusters, galaxies, comets, etc.). In effect the stellar visual magnitude reach is extended from about 13.8 of an 8" telescope or 14.3 of a 10" telescope to about 14.7. And yet at f4.9 this telescope affords the contrast and clarity qualities required to observe the moon, and planets; the XT12 actually reveals changes throughout the observing season! With a comparatively small central obstruction of about 5 per cent (by area), and fewer optical surfaces, the contrast and brightness can actually surpass more expensive designs such as the 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 a 12" telescope has a primary mirror of 12 inch (30.5cm) in diameter.

Right: Optical arrangement of Newtonian Reflecting telescope (38,882). Click on image to see enlarged view (187,513 bytes)

The Primary mirror of the XT12 telescope is precisely mounted in a new nine point Floatation 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.

Left: Pyrex® Parabolic Primary Mirror of an Orion Dobson telescope in it's Cell (16,559 bytes). Click on image to see enlarged view (68,383 bytes).

In a departure from most imported economical reflecting telescopes, the Primary Mirror of the XT12 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; 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 and practical specification.

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 XT12 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, and so this mark has no adverse impact on the optical performance.

Right: XT-10 IntelliScope™ showing Secondary Mirror holder, four vane Spider, Collimatable Aluminum 2" Focuser with Eyepiece, 50mm finder, and Navigation Knob. (17,089 bytes). The IntelliScope™ Control shown is optional.

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 overall 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 other Orion XT telescopes employ a rolled steel tube with a pressed seam. But the XT12 demand better rigidity and durability and so the tube assembly is rolled and welded lengthwise. 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. The XT Intelliscope telescopes models optical tube is finished with a contemporary deep bronze metallic enameled, this is finished internally in a black anti reflection paint.

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 a continuously smooth motion of the telescope in both axes. The bearings are adequate for the load and permit quite smooth movements while following celestial objects. If the telescope is assembled by Company Seven for pickup in our showroom (an optional service which is not mandated by us) then we do provide some hardware changes and adjustments which improve the motion and longevity even further.

Orion's engineers not only streamlined the stable Dobsonian base, but they also provided a lighter weight contemporary structure to the Base Side Arms. This provides a reasonable balance between light weight and rigidity and this is suitable for observing at the more common observing environments with calm nights. However, if you plan to observe from sites that are prone to gusting winds then you will notice how there is more of a tendency to lateral flexure (across the longitudinal axis of the optical tube, or left to right) of the XT12 than with its smaller cousins. This is due to the length of the fork tines and their relatively thin profile. It is possible for anyone with simple carpentry skills to install some stiffening ribs to the side boards of the carriage but we doubt many people will find this to be a practical concern.

IntelliScope™ Larger amateur Dobsonian telescopes often incorporate setting circles as an option which are helpful for locating objects by their cataloged coordinates. Many people find the beauty of a Dob is in their no-frills simplicity - they just work however, the modularity of the IntelliScope™ give you the choice. The IntelliScope™ system provides the user of the telescope the ability to quickly locate any of more than 14,000 fascinating celestial objects that come up in the Northern and Southern hemispheres with pushbutton ease!

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 IntelliScope™ 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 IntelliScope™ Computer Control is included as standard equipment with each new IntelliScope™ telescope. This makes locating and viewing even the most elusive deep-sky curiosities becomes a "no brainer." Just select an object to view from the controller's database. High-resolution, 9,216-step digital encoders integrated in the telescope then pinpoint the object and the display guides the operator to point the telescope right to it. The backlit LCD display facilitates reading the information, and preserving night vision. Choose from dozens of additional menu options, including tours of the best deep-sky gems each month and identification of any object in the field of view. Oh, so that's the Cat's Paw Nebula!

Full IntelliScope™ object-location functionality can be added at any time with purchase of the optional plug-in Controller.

The XT12 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.

Right: optional Holster for the IntelliScope™ Control (32,298 bytes). Easily slides on or off of two screws for transport. Click on image to see enlarged view (56,680 bytes).

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 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™ XT12 include:

A set of accessories provided to get you up and running on the first night out!

• Orion 25mm Plossl Eyepiece (50X providing 0.90 Degree Field of View)
• Orion 10mm Plossl Eyepiece (126X providing 0.39 Degree Field of View)
• Orion 9x 50mm Finderscope
• Quick release three point spring loaded adjustment Finder Mounting Bracket
• Collimation Cap (slips into focuser to help collimate telescope)
• Eyepiece Holder for 1.25" and one 2" eyepieces or accessories
• Center marked Primary Mirror (to ease collimation)
• Easy On-Off OTA Cover

  Innovative Design!
  

• Lightweight rolled and welded steel tube construction with cast aluminum end rings
• Exterior is finished in durable deep bronze metallic enamel, interior in antireflection Bblack
• CorrecTension friction optimization system for variable yet smooth friction/drag on Altitude Bearings
• Low-mass molded expertly finished Parabolic Primary Mirror made of Pyrex® a glass optimized for optical use
• Mirrors are aluminized, over coated with a transparent Silicon Monoxide protective coating assuring good longevity
• Adjustable Mirror Cell with spring-loaded collimation thumbscrews support the lightweight Primary Mirror. Aids ventilation for faster cool-down time
• Optics hand finished and tested on a 125 line Ronchi
• Silky smooth cast and machined aluminum Focuser with Drawtube Lock, with collimation adjustments
• Slip Fit 2 inch to 1.25" Reducer
• Convenient Grip/Carrying Handle on the Base

Receive a FREE Starry Night Special Edition software suite. Both the highly acclaimed planetarium software by Imaginova "Starry Night Special Edition" with a bonus "SkyTheatre" DVD are included FREE with purchase of any Orion-brand astronomical telescope from Company Seven.

"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).
Click on image to view enlargement (85,180 bytes).

XT12 Telescope Specifications:

Primary Mirror Effective Aperture: Secondary Mirror Minor Axis: Length of Optical Tube Assembly: Optical Tube Assembly Front Cell Diameter: Optical Tube Assembly Outer Diameter: Height from Eyepiece to Ground: Height of the Base / Carriage: Maximum Diameter of the Base / Carriage: Focuser Design: Drawtube Travel: Weight of Optical Tube Assembly: Weight of Carriage: Effective Light Gathering Power: Magnitude Limit Visual: Warranty:

12.06 inches / 306.3 mm 2.7 inches / 68.58 mm 58.3 inches / 148 cm (with lens cover) 14.25 inches / 36.2 cm 13.45 inches / 34.2 cm 56.7 inches / 144cm (pointing overhead) 30 inches / 76 cm 26 inches / 66 cm Rack and Pinion 1.5 inches / 38 mm 50 lbs. / 22.7 kg 33 lbs. / 15 kg about 1500X that of human Eye (actual throughput) about 14.7 One Year

* Measured by Company Seven, specifications are subject to change without notice.

FURTHER READING

To 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 Orion SkyQuest™ XT10 Intelliscope series Dobsonian telescopes. Includes unpacking instructions, parts list, instructions for the use, maintenance, and typical accessories. Publication content by Orion Telescopes and Binoculars, all rights reserved. From Company Seven's Archives. 1,349,005 bytes (in Acrobat Reader ".pdf" format).

COMPANY SEVEN'S ASSEMBLY & TESTING SERVICE:

Orion has been quite good at having 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.

"a series of subtle improvements that can transform an instrument into something wonderful"

As 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 (some years from now you will probably 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 telescope should work. We know the tricks to make the telescope move smoother up and down, left and right. We know how to make it last longer: 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 work so that our telescopes will perform as well as experience shows they 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.

"expert counsel brings value to a transaction, and profit should be the reward for a job well done"

SUGGESTED ACCESSORIES

1. Guide book: "Backyard Astronomers Guide" or "Nightwatch" by Terrence Dickinson, or "Starware" by Phil Harrington. For the novice from age 8 to 15 or so up to adult. Good introductions to astronomy, the use of telescopes, and their accessories. Easy introductions to finding ones way around the night sky.

2. Telrad illuminated sight: to aid one in finding and centering objects in the main telescope, and learn the sky by "star hopping" from one object to another. Especially helpful if you choose not to buy the Computer Controller (above).

3. David H. Levy Guide to the Stars Planisphere If you are not familiar with the night sky then Company Seven recommends you buy a good simple Planisphere which makes it very easy for one to find out what constellations and major deep sky objects are overhead at any given time of the day or night.

   The night sky is mapped with the Constellations being those patterns recognizable to man since time immemorial. Constellations can be thought of as countries or states on a world map, where if you seek the Grand Canyon then you know to find Arizona. While in the night sky when one seeks the Great Nebula then one looks toward the Constellation Orion. The Planisphere is a two piece assembly consisting of one disc with a chart of the entire night sky, and an attached overlay disc with a transparent window and surrounding mask to simulate the horizons. The overlay is dialed to line up its local time indicator marks with the Month and Day printed around the edge of the chart disc, and so when properly set this will reveal what parts of the sky may be seen at any time of the year. The print is easy to read under day or red light.
   

4. Once you begin to understand the way the night sky works with your Planisphere, the next step we suggest is to buy the Orion DeepMap 600 folding laminated Star Chart, edited by Steve Peters. Originally printed in 1997, the revised "Orion DeepMap 600" is among those indispensable publications that Company Seven recommends to anyone interested in learning their way around the night sky. The editor Steve Peters conceived of this as a very helpful device for anyone interested in astronomy and who may little or no observational experience. This has become the most popular chart of the night sky among our customers who are new to the hobby and who buy a telescope or binocular and now seek out what to see and when. This is often bought as a economical but valued and durable gift.

   Fully color illustrated, it is the first-ever star chart that folds up like a road map! DeepMap 600 shows the positions of more than six hundred of the finest celestial objects visible from the Northern Hemisphere. Each of these objects are plotted on a giant 33 x 21 inch full-color star chart by world-renowned celestial cartographer Wil Tirion. But what really makes this star chart invaluable is its convenience; it folds "accordion style" into a thin, pocket-size 4-¾ x 10-½ inches format - just like a road map!

   The chart is easy to read, and you will see more of the night sky when reading this with an optional red flashlight
   

5. Red LED Flashlight such as the Rigel Skylite to help one set up and use a telescope, and to read charts or a planisphere without adversely impacting the observers night vision.

6. Orion Cheshire Sight Collimating tool ($39) with optional "New Perspectives on Newtonian Collimation: Principles and Procedures" booklet ($8.00). Or for those who want a very accurate, and easy to use collimator then we recommend you consider our holographic Glatter Laser Collimator devices; even though documentation is included these devices require some training of the user to obtain best results, and our staff is more than capable to help you learn how to use these.
   

7. Neutral Density and Color Filters to attenuate the brightness of the Moon and Planets better revealing subtle features.
   

8. Sky Light Pollution Rejection Filter to reduce the greenish or golden background glow from city lights and darken the sky background - aid seeing faint Nebulae.
   

9. Improved 2" to 1.25" accessory adapter with non-marring clamp to securely hold eyepiece, threaded to accept 48mm filters so that you will only need to buy one standard size filter for use with either 1.25" or 2" eyepieces.
   

   

10. Orion fitted Carrying Bag (Model No. 15187) for safer, and more convenient transport the telescope optical tube assembly. Keep in mind that these are very convenient and lightweight bags, but are not suitable for shipping a telescope.
    

11. Eyepieces: Orion includes two eyepiece with this telescope, 10mm and 25mm Plossls. Typically astronomers will wish to initially set up the telescope with at least two or three 1.25" or 2" eyepieces to address:
    
    • Low magnification: for views of the faint deep sky objects a 32mm to 35mm focal length eyepiece.
      

    • Middle Magnification eyepiece - usually between 80 to 120X, for views of the full Moon, Star Clusters, etc.
      

    • High magnification: 200X or more for views of the planets
      

    Eyepiece designs such as the Plossl, Orthoscopic are acceptable. If you object to less than perfect images particularly at the edge of the field, and if you require long eye relief (distance from lens to the eye) to accommodate spectacles, then Company Seven recommends eyepieces of advanced designs such as those pioneered by Al Nagler, founder of the TeleVue company. TeleVue's advanced designs include the "Nagler", "Radian", or "Panoptic" series eyepieces. These oculars will provide the widest clear, and flat field images bringing out the most in your telescope (and many other) telescopes. Wider field of views are also desirable since as the Earth rotates and objects drift across the field of view, a wide angler ocular shows an object for some time longer before having to adjust the telescope.
    

    Please refer to the brochure and the test report/data from Company Seven enclosed with our telescopes for detailed characterizations of suggested eyepieces:

    Eyepiece	Magnification	Actual field of view	Exit pupil
    35mm Panoptic	43x	1.5 degrees	7.1mm
    32mm Plossl	47x	1 degree	6.5mm
    31mm Nagler Type 5	48x	1.6 degrees	6.3mm
    25 Plossl (included)	60x	0.75 degrees	5.1mm
    16mm Nagler Type 5	94x	.84 degrees	3.3mm
    15mm Plossl	100x	0.48 degrees	3mm
    12mm Nagler Type 4	125x	0.65 degrees	2.4mm
    10mm Plossl (included)	150X	0.31 degrees	2mm
    9mm Nagler Type 6	167X	0.47 degrees	1.8mm
    7mm Nagler Type 6	214x	0.4 degrees	1.4mm

12. Equalizer: A slip fit machined bronze, heavy 2 to 1.25 inch diameter reducer adapter. Helps to keep telescope balance when switching to and from light and heavy accessories and eyepieces. Particularly helpful when using telescope with Alt-Azimuth mounts.
     
13. Barlow or TeleVue "Powermate" Lens: Company Seven suggests you consider any of a number of 1.25 inch or 2 inch diameter Barlow lenses that we offer to double or more than triple your magnification. Furthermore, these accessories can project an image farther from the focuser to attain focus with most 35mm SLR cameras, optional accessories such as binocular viewers, etc. Contact Company Seven for suggestions on how to to best meet your goals.

14. Cooling Accelerator Fan: a mirror with as much mass as that provided with the XT12 can store a good degree of heat or cold. When one is quickly moving the telescope from one location to another where the temperature differences are pronounced then the telescope should be allowed to "acclimate" and this may take some time - even hours. Having an optional cooling fan installed.

    Orion offers an optional Cooling Accelerator Fan. This accessory speeds up the cooling of your big reflector's optics to ambient temperature with its small, quiet fan. It attaches to pretapped and threaded holes in the mirror cells of Orion SkyQuest XT-8, XT-10 and XT12 Dobsonians, Orion Atlas 8 and Atlas 10 reflectors, and the Orion SkyView Pro 8 reflector. Mounting screws are supplied. It runs on the 12 volts DC power supplied by the included battery pack, which uses eight D-cell batteries (not included). You can run the fan prior to observing, then turn it off, or you can even keep it running while observing; there is no noticeable vibration. Battery life is about 13-14 hours of continuous operation. Also compatible with 12-volt field battery rechargeable power packs.

15. The XT telescopes put the eyepiece at position that is only about 4 to 5 feet (1.2 to 1.5 meters) from the ground. Since most of our customers are taller than that, they will find it uncomfortable to stand bent over to observe for extended periods. For a much more enjoyable and comfortable observing experience, Company Seven recommends the Observing Chair; this is our most comfortable, flat folding, adjustable height seat. It is not inexpensive, but is so practical and can be used for camping or other times when a comfortable portable seat is desired.

16. Equatorial Mount: being constructed with a metal tube, at some time in the future you could buy a good quality equatorial mount and improve the usability of this telescope to attain its high magnification potential. A telescope of this length and torque requires a good quality, rigid platform to support it and there are a number of choices; we recommend you call us to discuss this at your convenience.