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If your astrophoto aspirations go beyond our 4.5" Imaging Reflector, step up to our Orion 6" Newtonian Imaging Telescope Optical Tube. Its performance compares head-to-head with many high-end refractors, but at a fraction of the price.
With its large 6" (150mm) parabolic mirror, this compact f/5 astrograph is optimized to fully illuminate the imaging chip of Orion StarShoot charge coupled device cameras and most digital SLRs, rendering exquisite detail even with short exposures. Added tube length in front of the secondary mirror blocks glare for improved contrast. Images are virtually coma free and, of course, there's no chromatic aberration.
The focuser is a low-profile, 2" Crayford-style design made of machined, anodized aluminum and it has coarse and fine (11:1) focus controls. It comes with a 1.25" compression ring adapter and a dovetail base for an Orion finder scope.
Put the Orion 6" Newtonian Imaging Telescope Optical Tube Imaging Reflector on any Orion mount and you'll have one awesome telescope for imaging! And when you want a break from that, just pop in an eyepiece for brow-raising visual adventures.
Available as optical tube assembly with no accessories.
Warranty
Limited Warranty against defects in materials or workmanship for one year from date of purchase. This warranty is for the benefit of the original retail purchaser only. For complete warranty details contact us at 800-676-1343.
Warning
Please note this product was not designed or intended by the manufacturer for use by a child 12 years of age or younger.
Product Support
Visit our product support section for instruction manuals and more
Specs
Best for viewing
Brighter deep sky
Best for imaging
Deep sky
User level
Beginner - Telescopes suited for beginners are easy to use and maintain. Very good optical and mechanical quality. A great first telescope that will show you the moon and planets.
Intermediate -Telescopes for the intermediate user are more robust in features and performance. Excellent quality in optics and mechanics, and more complex in use. An intermediate telescope will allow an enthusiast to "grow" in the hobby.
Advanced - Advanced telescopes are high performance, with exceptional quality. They may require more commitment to use in set-up time and technical savvy. Some advanced telescopes are easy-to-use but large and heavy. An advanced telescope is a purchase for a lifetime.
Expert - Expert telescopes offer uncompromising optical and mechanical quality for the most demanding amateur astronomer. They may be technically involved or designed for specialized use, such as astrophotography or detailed deep sky observation. They carry a premium price; but are designed to provide the ultimate performance in the field.
Intermediate
Optical design
A small, quality achromatic refractor of 60mm to 80mm aperture makes a fine starter scope for observing the Moon and major planets. They're affordable ($100 to $350), portable, and maintenance-free, all desirable factors if you're just "testing the waters" of Astronomy. If nebulas and galaxies are your main interest, a Newtonian reflector or Schmidt-Cassegrain is the way to go. Moving up to a 90mm or 100mm refractor will snare more objects and provide better performance, for a higher price. Renowned for crisp, sharp images, refractors are the priciest per inch of aperture of all telescope types. A refractor is the scope of choice if you will be doing most of your stargazing from city or suburbs, where the night skies are moderately light-polluted. Since viewing is restricted mostly to the Moon and planets a big scope would only amplify the skyglow, yielding poor washed out images. Reflectors Newtonian reflectors are great all-around scopes, offering generous apertures at affordable prices. They excel for both planetary and deep-sky viewing. Of course, the larger the aperture, the more you'll see. Smaller, 3" and 4.5" equatorially mounted Newtonians will provide a nice "survey" of celestial luminaries, and they maintain their portability. Six-inch and 8" Newts have enough aperture to deliver captivating images of fainter star-clusters, galaxies, and nebulas-especially in a reasonably dark sky. Although the 6" to 8" Newts are bulkier and weigh more, with a Dobsonian mount they are easily manageable by one person making them a wonderful beginner scopes. Dobsonian-mounted reflectors have lower price tags than their equatorial counterparts, starting in the mid-$300s for a 6" Dob. Schmidt-Cassegrains If portability is important to you, you might want to consider a "catadioptric" scope such as a Schmidt-Cassegrain or Maksutov-Cassegrain. They pack a hefty aperture into a very compact tube. An 8" Schmidt-Cassegrain provides excellent views of the Moon, planets, and deep-sky objects, and is well suited for astrophotography. Schmidt-Cassegrains should be considered as an investment priced over $1000 for the most basic 8" models (and hundreds more to outfit it for astrophotography). The Bottom Line Now that you've received the crash course on telescopes, here's some parting advice for aspiring astronomers: Get as much aperture as you can reasonably handle. Big aperture is desirable, however you don't want to end up with a scope that is too big or complicated to conveniently set up, haul around-and use! Also, avoid those gee-whiz, techno-toy scopes with the hefty price tags that are showing up in the big chain stores. For a first telescope, we recommend a basic refractor of 90mm aperture or smaller, or a Newtonian reflector of 6" aperture or less, unless you're really committed. After you've learned the basics of observing and developed an appreciation for the hobby, then you can move up to a bigger, fancier scope.
Reflector
Optical diameter
The optical diameter (also known as aperture), is the size of the telescope's main light collecting lens or mirror, measured in millimeters or inches. As the diameter increases, more light is collected and the resolution increases.
150mm
Focal length
The focal ratio of an optical system is the ratio of a telescope's focal length to its aperture. Short focal ratios (f/5, f/4.5) produce wide fields of view and small image scales, while long focal lengths produce narrower fields of views and larger image scales.
750mm
Focal ratio
The focal ratio of an optical system is the ratio of a telescope's focal length to its aperture. Short focal ratios (f/5, f/4.5) produce wide fields of view and small image scales, while long focal lengths produce narrower fields of views and larger image scales.
f/5.0
Optics type
Newtonian reflectors will have either a spherical shaped mirror, which is less expensive to produce, or a higher quality parabola, which does not result in spherical aberration. Cassegrain telescopes routinely use spheres in addition to other lenses in the optical path to correct for residual spherical aberration.
Refractors use a series of lenses to provide a clear image. Designs range from a standard air-spaced doublet (two lenses in a row) to exotic designs such as oil-spaced triplets and 4-element multi group lenses.
Parabolic
Glass material
Refractors use glass lenses to focus the light, and the glass material plays an important role in the quality of the resulting image. Standard achromatic refractors routinely use Crown and Flint for the two elements, but more expensive apochromatic refractors can use ED (extra low dispersion) glass for one or more of the lenses. Reflector mirrors are made from glass with different levels of thermal expansion. Standard mirrors are made from material such as Soda-Lime Plate glass and BK-7 glass. Glass with Pyrex or other low thermal expansion material will not change shape as dramatically during the cool-down period, resulting in more stable images during this period.
Soda-lime plate
Resolving power
The theoretical resolving power of a telescope can be calculated with the following formula: Resolving power (in arc seconds) = 4.56 divided by aperture of telescope (in inches). In metric units, this is: Resolving power (in arc seconds) = 116 divided by aperture of telescope (in millimeters). Note that the formula is independent of the telescope type or model, and is based only upon the aperture of the telescope. So the larger the telescope's aperture, the more it is capable of resolving. This is important to keep in mind when observing astronomical objects which require high resolution for best viewing, such as planets and double stars. However, it is usually atmospheric seeing conditions (not the telescope) which limits the actual resolving power on a given night; rarely is resolution less than one arc-second possible from even the best viewing locations on Earth.
0.77arc*sec
Lowest useful magnification
Lowest useful magnification is the power at which the exit pupil becomes 7mm in diameter. Powers below this can still be reached with the telescope to give wider fields of view, but the image no longer becomes brighter at a lower power. This is due to the fact that the exit pupil of the telescope (the beam of light exiting the eyepiece) is now larger than the average person's dark adapted pupil, and no more light can fit into the eye.
21x
Highest useful magnification
The highest practical limit is different from the often used "highest theoretical magnification" specification. The "theoretical" limit generally is 50x the aperture of the scope in inches (2x the aperture in mm). So for example, an 80mm refractor is capable of 160x, and a 10" telescope is theoretically capable of 500x magnification.
But after approximately 300x, theory breaks down and real world problems take over. The atmosphere above us is constantly in motion, and it will distort the image seen through the telescope. This effect may not be noticeable at lower powers, but at higher powers the atmosphere will dramatically blur the object, reducing the quality of the image. On a good night (a night where the air above is steady and the stars aren't twinkling), the practical upper limit of a large telescope is 300x, even thought the theoretical limit may be much higher. This doesn't mean the scope will never be able to reach those higher "theoretical" powers - there will be that rare night where the atmosphere is perfectly still and the scope can be pushed past it's practical limit, but those nights will be few and far between.
300x
Highest theoretical magnification
300x
Optical quality
"Diffraction Limited" means that the limits of image detail are determined by the physical properties of light, and not by optical defects in the telescope.
Diffraction limited
Focuser
2" dual-speed Crayford
Secondary mirror obstruction
58mm
Secondary mirror obstruction by diameter
38%
Secondary mirror obstruction by area
14%
Mirror coatings/over-coatings
Aluminum & Silicon Dioxide
Mount type
Optical Tube without Mount
Astro-imaging capability
The astro-photographic capability of the telescope is based on the style, stability, and accuracy of the mount and tripod. Telescopes on either very lightweight mounts or non tracking mounts (such as Dobsonians) are capable of only very short exposures such as lunar photographs. If a motor drive is attached to an equatorial mount, even a small lightweight mount is capable of capturing some planetary detail. Larger EQ mounts that utilize very precise tracking and excellent stability are capable of longer exposure deep-sky photography.
Lunar, planetary & long exposure
Length of optical tube
30.5 in.
Weight, optical tube
10.5 lbs.
Additional included accessories
1.25" compression-fit eyepiece adapter
Other features
Dual-speed (11:1) focuser
Shipping Info
Orders received by noon Pacific Time for in-stock items ship the same business day. Orders received after noon will ship the next business day. When an item is not in-stock we will ship it as soon as it becomes available. Typically in-stock items will ship first and backordered items will follow as soon as they are available. You have the option in check out to request that your order ship complete, if you'd prefer.
A per-item shipping charge (in addition to the standard shipping and handling charge) applies to this product due to its size and weight. This charge varies based on the shipping method.
Standard Delivery: $0.00 3 Day Air Delivery: $62.00 2 Day Delivery: $62.00 Next Day Delivery: $72.00
How can I check the collimation of my reflector?
Collimation is the process of adjusting the telescope’s mirrors so they are perfectly aligned with one another. Your telescope’s optics were aligned at the factory, and should not need much adjustment unless the telescope is handled roughly. Mirror alignment is important to ensure the peak performance of your telescope, so it should be checked regularly. Collimation is relatively easy to do and can be done in daylight. To check collimation, remove the eyepiece and look down the focuser drawtube. You should see the secondary mirror centered in the drawtube, as well as the reflection of the primary mirror centered in the secondary mirror, and the reflection of the secondary mirror (and your eye) centered in the reflection of the primary mirror. If anything is off-center, proceed with the collimation procedure. The faster the f/ratio of your telescope, the more critical the collimation accuracy.
Can I center the secondary mirror under the focuser with the aid of the Orion LaserMate?
You can, but it requires marking the center of the telescope’s secondary mirror in the same way the center of the telescope’s primary mirror was marked. This is generally undesirable due to the large area of the supplied collimation targets compared to the total area of the secondary mirror. Since centering the secondary mirror under the focuser is an adjustment that very rarely, if ever, needs to be done, we recommend simply making this adjustment by eye. We’ve tried it both ways and it is just as easy to do it without the Orion LaserMate.
Is the LaserMate Collimator dangerous?
The LaserMate emits laser radiation, so it is important not to shine the beam into your or anyone’s eye. During the collimation procedure, it is also important to avoid direct reflections of the laser beam into your eye. Rather, look only at off-axis reflections to determine the position of the laser spot on the mirrors. It is safe to view the laser when it is reflected off a surface that will diffuse the light, such as the bottom surface of the LaserMate. It is also safe to view the reflection off a mirror surface as long as the beam is not directed into your eye. Because of the potential danger from the laser beam, store your LaserMate out of the reach of children.
How do I align a finder scope?
Before you use the finder scope, it must be precisely aligned with the telescope so they both point to exactly the same spot. Alignment is easiest to do in daylight, rather than at night under the stars. First, insert a low power telescope eyepiece (a 25mm eyepiece will work great) into the telescope’s focuser. Then point the telescope at a discrete object such as the top of a telephone pole or a street sign that is at least a quarter-mile away. Position the telescope so the target object appears in the very center of the field of view when you look into the eyepiece. Now look through the finder scope. Is the object centered on the finder scope’s crosshairs? If not, hopefully it will be visible somewhere in the field of view, so only small turns of the finder scope bracket’s alignment thumb screws will be needed. Otherwise you’ll have to make larger turns to the alignment thumb screws to redirect the aim of the finder scope. Use the alignment thumb screws to center the object on the crosshairs of the finder scope. Then look again into the telescope’s eyepiece and see if it is still centered there too. If it isn’t, repeat the entire process, making sure not to move the telescope while adjusting the alignment of the finder scope. Finder scopes can come out of alignment during transport or when removed from the telescope, so check its alignment before each observing session.
How do I calculate the magnification (power) of a telescope?
To calculate the magnification, or power, of a telescope with an eyepiece, simply divide the focal length of the telescope by the focal length of the eyepiece. Magnification = telescope focal length ÷ eyepiece focal length. For example, the Orion 6" Newtonian Imaging Reflector Telescope, which has a focal length of 750mm, used in combination with a 25mm eyepiece, yields a power of: 750 ÷ 25 = 30x.
It is desirable to have a range of telescope eyepieces of different focal lengths to allow viewing over a range of magnifications. It is not uncommon for an observer to own five or more eyepieces. Orion offers many different eyepieces of varying focal lengths.
Every telescope has a theoretical limit of power of about 50x per inch of aperture (i.e. 300x for the Orion 6" Imaging Reflector). Atmospheric conditions will limit the usefullness of magnification and cause views to become blurred. Claims of higher power by some telescope manufacturers are a misleading advertising gimmick and should be dismissed. Keep in mind that at higher powers, an image will always be dimmer and less sharp (this is a fundamental law of optics). With every doubling of magnification you lose half the image brightness and three-fourths of the image sharpness. The steadiness of the air (the “seeing”) can also limit how much magnification an image can tolerate. Always start viewing with your lowest-power (longest focal length) eyepiece in the telescope. It’s best to begin observing with the lowest-power eyepiece, because it will typically provide the widest true field of view, which will make finding and centering objects much easier After you have located and centered an object, you can try switching to a higher-power eyepiece to ferret out more detail, if atmospheric conditions permit. If the image you see is not crisp and steady, reduce the magnification by switching to a longer focal length eyepiece. As a general rule, a small but well-resolved image will show more detail and provide a more enjoyable view than a dim and fuzzy, over-magnified image.
What are practical focal lengths to have for eyepieces for my telescope?
To determine what telescope eyepieces you need to get powers in a particular range with your telescope, see our Learning Center article: How to choose Telescope Eyepieces
How do I best view Deep-Sky Objects?
Most deep-sky objects are very faint, so it is important that you find an observing site well away from light pollution. Take plenty of time to let your eyes adjust to the darkness. Don’t expect these objects to appear like the photographs you see in books and magazines; most will look like dim gray “ghosts.” (Our eyes are not sensitive enough to see color in deep-sky objects except in few of the brightest ones.) But as you become more experienced and your observing skills improve, you will be able to coax out more and more intricate details. And definitely use your low-power telescope eyepieces to get a wide field-of view for the largest of the deep-sky objects. For more details, see our learning center article Observing Deep Sky Objects
How do I clean the reflecting mirror of my telescope?
You should not have to clean the telescope’s mirrors very often; normally once every other year or even less often. Covering the telescope with the dust cover when it is not in use will prevent dust from accumulating on the mirrors. Improper cleaning can scratch mirror coatings, so the fewer times you have to clean the mirrors, the better. Small specks of dust or flecks of paint have virtually no effect on the visual performance of the telescope. The large primary mirror and the elliptical secondary mirror of your telescope are front-surface aluminized and over-coated with hard silicon dioxide, which prevents the aluminum from oxidizing. These coatings normally last through many years of use before requiring re-coating. To clean the secondary mirror, first remove it from the telescope. Do this by holding the secondary mirror holder stationary while turning the center Phillips-head screw. Be careful, there is a spring between the secondary mirror holder and the phillips head screw. Be sure that it will not fall into the optical tube and hit the primary mirror. Handle the mirror by its holder; do not touch the mirror surface. Then follow the same procedure described below for cleaning the primary mirror. To clean the primary mirror, carefully remove the mirror cell from the telescope and remove the mirror from the mirror cell. If you have an Orion telescope, instructions to remove the primary mirror are included in your instruction manual. Do not touch the surface of the mirror with your fingers. Lift the mirror carefully by the edges. Set the mirror on top, face up, of a clean soft towel. Fill a clean sink, free of abrasive cleanser, with room-temperature water, a few drops of mild liquid dishwashing soap, and, if possible, a capful of rubbing alcohol. Submerge the mirror (aluminized face up) in the water and let it soak for a few minutes (or hours if it’s a very dirty mirror). Wipe the mirror under water with clean cotton balls, using extremely light pressure and stroking in straight line across the mirror. Use one ball for each wipe across the mirror. Then rinse the mirror under a stream of lukewarm water. Before drying, tip the mirror to a 45 degree angle and pour a bottle of distilled water over the mirror. This will prevent any tap water dissolved solids from remaining on the mirror. Any particles on the surface can be swabbed gently with a series of cotton balls, each used just one time. Dry the mirror in a stream of air (a “blower bulb” works great), or remove any stray drops of water with the corner of a paper towel. Water will run off a clean surface. Cover the mirror surface with tissue, and leave the mirror in a warm area until it is completely dry before replacing in the mirror cell and telescope.
Does my telescope require time to cool down?
As a general rule, telescopes should be allowed to cool down (or warm up) before they are used. If you bring optics from a warm air to cold air (or vice versa) without giving it time to reach thermal equilibrium, your telescope will give you distorted views. Allow your telescope 30 minutes to an hour to reach the temperature of the outdoors before using. When brining your telescope from cool temperatures to warm temperatures, leave any protective caps off until the telescope has warmed-up to prevent condensation. Storing your telescope in the garage or shed where the temperature is closer to the outside temperature will reduce cool down times.
How do I take solar astrophotos?
By attaching a camera body to a telescope, in effect using the scope as a telephoto lens, you can take striking photographs of the Sun. Only attempt this if the telescope is equipped with the proper solar filter. Solar filters are coated to a neutral density of 5, which reduces the light about 100,000 times. Depending on the aperture and focal length of your telescope and “seeing” conditions, you will need to experiment to find the best exposure time for your equipment. We recommend starting with an ISO rating of around 400. At prime focus, start with an exposure of about 1/250 second. Experiment with different shutter speeds. When using higher magnifications, longer exposures will generally be necessary. If you are a beginner in astrophotography and need further information, there are books available that cover this subject completely. Do not be discouraged if your first attempts at solar photography are less than desired. The Sun is very difficult to photograph because of poorer “seeing” conditions caused by unavoidable heat currents associated with daytime viewing. The highest possible resolution for any land-based telescope, regardless of location, is about 1 arc second. Ideal seeing for any location will be available less than 5% of the time. It may be some consolation to consider that your results could equal those at professional observatories, as larger apertures and location have little, if any, advantage. During bad seeing conditions, it may help to “stop down” apertures over 5“ with an off-axis mask.
Reviews
Orion 6" f/5.0 Newtonian Imaging Reflector Telescope OTA
8
Orion's 6" Newtonian Imaging Reflector is perfect for use with a CCD or DSLR camera for excellent astrophotography results. The images taken are sharp and true to color. And the added length in this scope helps block glare for improved contrast.
Orion 6" f/5.0 Newtonian Imaging Reflector Telescope OTA
8
Orion's 6" Newtonian Imaging Reflector is perfect for use with a CCD or DSLR camera for excellent astrophotography results. The images taken are sharp and true to color. And the added length in this scope helps block glare for improved contrast.