6" Omni XLT 150 Equatorial f/5 reflector with Starbright XLT multicoated mirrors

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CG-4 mount
The CG-4 German equatorial mount supplied with this Celestron telescope does not come with a motor drive as standard equipment, but its manual worm gear drive slow motion controls will let you smoothly track celestial objects for visual observing with only an occasional twist of the wrist. Adding optional dual axis motor drive #MDCG4D will keep objects centered in the eyepiece continuously. If family viewing is planned, a motor drive means you don’t have to worry about the object being observed drifting out of view while changing observers. This is especially handy when observing with small children or groups of people (at star parties or scout meetings, for example). If astrophotography is in the cards, the #MDCG4D motor drive/drive corrector is essential.
    The mount uses precision ball-bearings in both the right ascension and declination axes to assure smooth and hitch-free motion of your scope across the skies. Built-in non-powered setting circles are provided to help you find objects by using their right ascension (hour) and declination (degree) coordinates as shown in a star chart or atlas. The right ascension hour circle is equipped with a vernier scale that lets you adjust the telescope position in right ascension to an accuracy of one minute.
    The standard manual right ascension and declination slow motion controls have easy-grip knobs that make manual tracking and small position adjustments a cinch. The extra-large control knobs are positioned so that they fall easily to hand when observing, so you don’t have to grope blindly for the knobs when you need to make adjust the scope’s position. To make a casual polar alignment for visual use quick and easy, there’s a latitude scale and fine adjustment controls in both altitude and azimuth. The mount can be used over a latitude range of approximately 20° to 60°. If astrophotography is in your plans, an optional polar finderis available to increase the accuracy of your alignment.
    The mount’s adjustable height tripod has 1.75” diameter stainless steel legs for strength and rigidity. There’s a center leg brace that locks the tripod legs firmly in place for excellent vibration-damping. The center brace is drilled with several holes that will hold your 1.25” and 2” eyepieces conveniently at hand and up and out of the dew-soaked grass. The no-tool locking knobs that adjust the height of the tripod are located on the inside of the tripod legs. This keeps them from snagging clothing in the dark, a thoughtful touch sure to be appreciated. The tripod adjusts over a height range of 33” to 47”. As with all tripods, it is at its most rigid and stable when at its lowest height.
    Two counterweights are supplied to balance the optical tube. The sliding counterweights are locked in place with a single hand-tighten thumbscrew each, making it easy to rebalance the scope if you add heavy accessories. The mount is easily capable of handling the scope and any reasonable combination of accessories you might want to add.
    An adjustable dovetail slide bar allows the optical tube to be quickly and precisely balanced fore and aft on the mount, eliminating the need for an extra counterweight to balance a camera or other accessories. Setup and takedown times are exceptionally fast, as no tools are required to assemble the mount and tripod and only a single large hand-tighten knob holds the optical tube in place. A second smaller lock knob prevents the tube from sliding off the mount should the hand-tighten knob loosen.
    The CG-4 equatorial head weighs 10 lbs (4.5 kg). The 7 lb (3.2 kg) and 4 lb (1.8 kg) counterweights total 11 lbs (5 kg). The tripod weighs 12.5 lbs (5.7 kg). Total weight of the complete mount set up to receive an optical tube is 33.5 lbs (15.2 kg).
This Celestron telescope has:

• 150mm f/5 Newtonian reflector optics
• StarBright XLT mirror multicoatings for the highest possible light transmission
• CG-4 German equatorial mount with ball bearings and stainless steel tripod
• 6 x 30mm finderscope
• 25mm 1.25” eyepiece (30x)
• bright wide angle deep space views, plus high-contrast performance inside the solar system
• 2-year warranty

    The Celestron Omni XLT 150 reflector combines very good 6” fast focal ratio Newtonian reflector optics with a solid German equatorial mount – at a surprisingly low price for a scope of its aperture and optical performance. It provides an excellent mix of performance, portability (despite its large aperture), stability, and features that any serious backyard astronomer can appreciate.
For the observer whose interests are primarily the fainter deep space objects, the Omni XLT 150 has a lot to offer. It has 459x the light-gathering capacity of even the sharpest dark-adapted eye, allowing you to see faint deep space wonders that would be otherwise invisible. The Celestron Omni XLT 150 works well visually from many city and suburban sites, as its f/5 focal ratio keeps moderately light-polluted sky backgrounds reasonably dark to avoid washing out faint nebula detail. As with any scope, however, transporting the Celestron Omni XLT 150 to a dark sky observing site will markedly improve its performance on broad, faint deep sky objects at low powers.
In addition, the 750mm focal length of this Celestron makes it easy to achieve the high powers needed for detailed lunar and planetary observing. Simply add an optional Barlow lens, and/or additional optional higher power eyepieces, and this Celestron telescope will provide you with crisp and sharply detailed close-up views of the Moon and planets.
The scope’s lightweight optical tube and easily assembled mount make it quick to set up and enjoy – either in your back yard or at a distant dark sky site. Its very good optical quality and very reasonable price make it an excellent buy for the beginning and advanced astronomer alike.

This Telescope’s Optical System . . .

  • Newtonian reflector optics: 6” (150mm) aperture, 750mm focal length, f/5 Newtonian parabolic mirror reflector using aspheric shaping technology for images that have virtually no spherical aberration and are free from the chromatic aberration of achromatic refractors. The optical tube is aluminum, to allow the mirrors to cool to ambient temperature more quickly. Also, the lower end of the tube is sealed to reduce image-degrading thermal currents within the optical tube. These features extend your undisturbed viewing time by minimizing the time you have to wait for the images to stabilize after you take your scope outside in the cold air of late fall or winter. The scope’s tube end rings are sturdy die cast aluminum, to protect the tube during transport and provide exceptionally rigid support for the optics. The mirror cell’s six-screw push/pull locking collimation system keeps the primary mirror aligned far longer than conventional mirror cells – so you spend more time observing, and less time adjusting the optics. The lightweight optical tube rotates in its felt-lined die cast cradle rings to bring the focuser and finder to the most comfortable viewing position. The mounting rings even include a built-in piggyback mount for wide field astrophotography (using an optional motor drive). The 27” long aluminum optical tube weighs only 12 lbs., making it easy to transport and assemble in the field.

  • Starbright XLT multicoated mirrors: Fully coated with multiple vacuum-deposited layers of high reflectivity aluminum. The aluminum coatings are enhanced with titanium dioxide for maximum reflectivity and overcoated with a protective layer of silicon monoxide (quartz) for long life. They are the same mirror coatings used on Celestron’s largest and most expensive optical systems.

  • Focuser: 1.25” metal rack and pinion type. Dual focusing knobs with rubber gripping surfaces for precise image control with either hand. The large focus knobs are easy to operate, even while wearing gloves or mittens in cold weather.

  • Eyepiece: Fully multicoated low power 1.25” 25mm (30x) eyepiece with a 1.67° field of view that’s over three times the diameter of the full Moon.

  • Finderscope: 6 x 30mm straight-through achromatic design, with a wide 7° field of view. Focuses by loosening the trim ring behind the objective lens cell, screwing the lens cell in or out to focus, and tightening the trim ring to lock in the correct focus.

  • Software: Comes with TheSky Level 1 sky-charting CD-ROM that has a database of 10,000 stars and objects it can plot and display on your Windows-based computer screen. That’s enough solar system and deep space detail to keep you busy observing for years, yet not so much that you’re overwhelmed by charts showing much more detail than your scope can usefully reveal. Custom sky chart printing lets you print out eyepiece finder charts to use with your telescope to help you locate and identify the planets and many famous and faint deep space nebulas, galaxies, and star clusters by star-hopping from object to object using your scope’s slow motion controls. There are 75 full color images of well-known celestial objects to help you identify them through your scope.

This Telescope’s Mount . . .

  • CG-4 German equatorial mount: The mount has setting circles in both right ascension and declination, worm gear drives and manual slow motion controls in both axes, a latitude scale and fine adjustment controls in both altitude and azimuth, two counterweights totaling 11 pounds so you can easily balance virtually any accessory load, and more. An optional dual axis DC drive/drive corrector is available for no-hands tracking of celestial objects and photography. It is not possible to upgrade to a computerized go-to drive system. For more details, click on the “mount” icon above.

  • Adjustable height tripod: The tripod has 1.75” diameter steel legs with a center leg brace for rigidity. It adjusts over a height range from 33” to 47”. Vibration damping characteristics are excellent. The center leg brace is drilled to form a convenient accessory tray that holds 1.25” and 2” eyepiece to keep them up out of the dew-soaked grass.

  • Dovetail tube mount: The scope’s optical tube fits into a set of felt-lined split and hinged tube rings that are bolted to a dovetail bar. The dovetail bar in turn slips into a dovetail groove on the mount’s equatorial head. Setup and takedown times are exceptionally fast, as is rebalancing the scope when changing accessory loads, as a single large hand-tighten knob holds the optical tube in place. A second lock knob prevents the tube from sliding off the mount should the hand-tighten knob accidentally loosen while observing. One of the tube rings has a piggyback camera mount built into it for casual long exposure wide-field astrophotography.

  • Two-year warranty: All Celestron telescopes have a two-year warranty, double that of competitive scopes.

What can you see through this 150mm Celestron reflector?

    With a short 750mm focal length and a huge light grasp 459 times that of the sharpest dark-adapted eye, the scope produces bright and wide-field images of the thousands of faint fuzzies outside the solar system – nebulas, galaxies, open star clusters, and more. With its 6” aperture, compact deep space objects – globular clusters, close binary star pairs, etc. – are sharply resolved. Using optional eyepieces and/or a Barlow to boost the magnification, you can also see subtle solar system details that are virtually invisible in smaller aperture scopes. You can study complex lunar craters, rilles, mountain ranges, and low contrast lunar ray detail. With reasonable seeing conditions, detail in Jupiter’s cloud belts and the Great Red Spot (actually closer in color to the Faint Pink Spot at this point in time) are visible, as are dusky markings on the face of Saturn and Cassini’s division in Saturn’s brilliant rings. Because of its great light-gathering capacity, you may need an optional neutral density filter to cut down the brightness of some solar system objects for maximum resolution.
Optically and mechanically refined, and very reasonable in cost for a big 6” aperture reflector, this Celestron Omni XLT 150 has enough optical performance to keep you busy for the rest of your life.

Highest Useful Magnification:
This is the highest visual power a telescope can achieve before the image becomes too dim for useful observing (generally at about 50x to 60x per inch of telescope aperture). However, this power is very often unreachable due to turbulence in our atmosphere that makes the image too blurry and unstable to see any detail.

On nights of less-than-perfect seeing, medium to low power planetary, binary star, and globular cluster observing (at 25x to 30x per inch of aperture or less) is usually more enjoyable than fruitlessly attempting to push a telescope's magnification to its theoretical limits. Very high powers are generally best reserved for planetary observations and binary star splitting.

Small aperture telescopes can usually use more power per inch of aperture on any given night than larger telescopes, as they look through a smaller column of air and see less of the turbulence in our atmosphere. While some observers use up to 100x per inch of refractor aperture on Mars and Jupiter, the actual number of minutes they spend observing at such powers is small in relation to the number of hours they spend waiting for the atmosphere to stabilize enough for them to use such very high powers.
Visual Limiting Magnitude:
This is the magnitude (or brightness) of the faintest star that can be seen with a telescope. The larger the number, the fainter the star that can be seen. An approximate formula for determining the visual limiting magnitude of a telescope is 7.5 + 5 log aperture (in cm).

This is the formula that we use with all of the telescopes we carry, so that our published specs will be consistent from aperture to aperture, from manufacturer to manufacturer. Some telescope makers may use other unspecified methods to determine the limiting magnitude, so their published figures may differ from ours.

Keep in mind that this formula does not take into account light loss within the scope, seeing conditions, the observer’s age (visual performance decreases as we get older), the telescope’s age (the reflectivity of telescope mirrors decreases as they get older), etc. The limiting magnitudes specified by manufacturers for their telescopes assume very dark skies, trained observers, and excellent atmospheric transparency – and are therefore rarely obtainable under average observing conditions. The photographic limiting magnitude is always greater than the visual (typically by two magnitudes).

Focal Length:
This is the length of the effective optical path of a telescopeor eyepiece (the distance from the main mirror or lens where the lightis gathered to the point where the prime focus image is formed). Focallength is typically expressed in millimeters.

The longer the focallength, the higher the magnification and the narrower the field of viewwith any given eyepiece. The shorter the focal length, the lower themagnification and the wider the field of view with the same eyepiece.

Focal Ratio:
This is the ‘speed’ of a telescope’s optics, found by dividing the focal length by the aperture. The smaller the f/number, the lower the magnification, the wider the field, and the brighter the image with any given eyepiece or camera.

Fast f/4 to f/5 focal ratios are generally best for lower power wide field observing and deep space photography. Slow f/11 to f/15 focal ratios are usually better suited to higher power lunar, planetary, and binary star observing and high power photography. Medium f/6 to f/10 focal ratios work well with either.

An f/5 system can photograph a nebula or other faint extended deep space object in one-fourth the time of an f/10 system, but the image will be only one-half as large. Point sources, such as stars, are recorded based on the aperture, however, rather than the focal ratio – so that the larger the aperture, the fainter the star you can see or photograph, no matter what the focal ratio.

This is the ability of a telescope to separate closely-spaced binary stars into two distinct objects, measured in seconds of arc. One arc second equals 1/3600th of a degree and is about the width of a 25-cent coin at a distance of three miles! In essence, resolution is a measure of how much detail a telescope can reveal. The resolution values on our website are derived using the Dawes’ limit formula.

Dawes’ limit only applies to point sources of light (stars). Smaller separations can be resolved in extended objects, such as the planets. For example, Cassini’s Division in the rings of Saturn (0.5 arc seconds across), was discovered using a 2.5” telescope – which has a Dawes’ limit of 1.8 arc seconds!

The ability of a telescope to resolve to Dawes’ limit is usually much more affected by seeing conditions, by the difference in brightness between the binary star components, and by the observer’s visual acuity, than it is by the optical quality of the telescope.

0.77 arc seconds
This is the diameter of the light-gathering main mirror or objective lens of a telescope. In general, the larger the aperture, the better the resolution and the fainter the objects you can see.
The weight of this product.
45.5 lbs.
Heaviest Single Component:
The weight of the heaviest component in this package.
21 lbs.
Telescope Type:
The optical design of a telescope.  Telescope type is classified by three primary optical designs (refractor, reflector, or catadioptric), by sub-designs of these types, or by the task they perform.
Based on Astronomy magazine’s telescope "report cards", scopes of this size and type generally perform as follows . . .
Terrestrial Observation:
Observing terrestrial objects (nature studies, birding, etc.) is usually possible only with refractor and catadioptric telescopes, and convenient only when the scope is on an altazimuth mount or photo tripod. Most reflectors cannot be used for terrestrial observing. Scopes with apertures under 5" to 6" are generally most useful for terrestrial observing due to atmospheric conditions (heat waves and mirage, dust, haze, etc.) that degrade the image quality in larger scopes. 
Lunar Observation:
Visual observation of the Moon is possible with any telescope. Larger aperture scopes will provide more detail than smaller scopes, thereby getting a higher score in this category, but may require an eyepiece filter to cut down the greater glare from the Moon's sunlit surface so small details can be seen more easily. Lunar observing is more rewarding when the Moon is waxing or waning as the changing sun angle casts constantly varying shadows to reveal craters and surface features by the hundreds.  
Planetary Observation:
Very Good
Binary and Star Cluster Observation:
Very Good
Galaxy and Nebula Observation:
Terrestrial Photography:
Photographing terrestrial objects (wildlife, scenery, etc.) is usually possible only with refractor and catadioptric telescopes, and convenient only when the scope is on an altazimuth mount or photo tripod. Most reflectors cannot be used for terrestrial photography. Scopes with focal ratios of f/10 and faster and apertures under 5" to 6" are generally the most useful for terrestrial photography due to atmospheric conditions (heat waves and mirage, dust, haze, etc.) that degrade the image quality in larger scopes.
Lunar Photography:
Photography of the Moon is possible with virtually any telescope, using a 35mm camera, DSLR, or CCD-based webcam (planetary imager). While an equatorial mount with a motor drive is not strictly essential, as the exposure times will be very short, such a mount would be helpful to improve image sharpness, particularly with webcam-type cameras that take a series of exposures over time and stack them together. Reflectors may require a Barlow lens to let the camera reach focus. 
Planetary Photography:
Star Cluster / Nebula / Galaxy Photography:
1 year
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Visual Accessories
Miscellaneous (1)
Kit of 1.25" Plössl eyepieces and visual accessories
by Celestron
  • 750mm f/5 Newtonian reflector optical tube with Starbright XLT multicoated mirrors
  • CG-4 German equatorial mount with setting circles, manual slow motion controls, and adjustable height steel leg tripod with combined spreader bar/accessory tray
  • 6 x 30mm straight-through finder
  • 1.25” rack and pinion focuser
  • 1.25” 25mm eyepiece (30x)
  • Dust covers
  • TheSky Level 1 star-charting CD-ROM software
  • Two-year warranty.
Celestron Omni XLT manual 3341 KB
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Celestron - 6" Omni XLT 150 Equatorial f/5 reflector with Starbright XLT multicoated mirrors

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Celestron - 6" Omni XLT 150 Equatorial f/5 reflector with Starbright XLT multicoated mirrorsFull-length image of scope on tripod.Colse-up of mount showing counterweights, altitude/azimuth fine adjustments, manual slow motion controls, dovetail bar and tube rings.Close-up showing finderscope, focuser, secondary mirror holder, tube rings.
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Our Product #: C150XLT
Manufacturer Product #: 31057
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Clear skies,

This Celestron Omni XLT 150 puts a big 6” aperture fast focal ratio reflector, with Starbright XLT multicoated mirrors for maximum light transmission, on a solid German equatorial mount. The result is an excellent mix of deep space performance, portability, and features at a price that’s extraordinarily low for so much light-gathering and so many features . . .

. . . our 39th year