Celestron 4.7" Omni XLT 120 Equatorial refractor with Starbright XLT optical multicoatings


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This Celestron Omni XLT 120 refractor puts large 4.7" aperture fully Starbright XLT multicoated achromatic optics on a solid German equatorial mount. The result is an excellent mix of performance, portability, and features at a price that's surprisingly low for a scope of this aperture . . .
Our Product #: C120XLT
Celestron Product #: 21090
Recommended Accessories

Product Description

This Celestron telescope has:
• 120mm f/8.3 achromatic refractor optics
• StarBright XLT 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 (40x)
• 2-year warranty

The Celestron Omni XLT 120 refractor combines quality 4.7" refractor optics with a solid German equatorial mount - at a very sensible price for a scope of its aperture and quality. It provides an excellent mix of performance, portability, stability, and features that any serious backyard astronomer can appreciate.

For the observer whose interests are the brighter solar system and deep space objects, the Omni XLT 120 has a lot to offer. It is exceptional for observing within the solar system. Its views of subtle lunar and planetary details are sharp and contrasty, bringing the planets to vivid life in the eyepiece.

It has a sensibly large aperture and diffraction-free images that make it surprisingly good for much deep space observing, as well. Binary stars and globular star clusters are particularly well-resolved and vivid, with the contrasting colors of many binary systems showing nicely. The brighter nebulas and galaxies stand out against a darker sky background than is possible in a comparably-priced reflector with its light-scattering diagonal mirror.

This Telescope's Optical System . . .

Refractor optics: 4.7" (120mm) aperture, 1000mm focal length, f/8.3 achromatic doublet lens using aspheric shaping technology for images that have virtually no spherical aberration. Chromatic aberration (spurious color) is present, but well controlled for a scope of this aperture. The lens cell is fully collimatable for optimum sharpness. The optical tube length is a very manageable 40".

Starbright XLT multicoated optics: Fully coated on all air-to-glass surfaces with multiple layers of magnesium fluoride and hafnium dioxide antireflection coatings for the highest possible light transmission and contrast. They are the same coatings used on Celestron's largest most expensive optical systems.

Lens cap/aperture stop: A protective lens cap is provided to cover the objective lens of the telescope and keep it dust-free when the scope is not in use. This lens cap has a built-in aperture stop in the center. When observing the Moon and planets, leaving the lens cap on the telescope with the aperture stop removed will reduce the scope's chromatic aberration (the faint halo of violet light or "spurious color" visible around very bright objects in all achromatic refractor telescopes). The scope's resolution will be slightly reduced, but eliminating the spurious color provides a generally more pleasing image for most observers. The lens cap should always be completely removed when observing faint deep sky objects such as nebulas and galaxies, where aperture (light-gathering) is essential and chromatic aberration is not an issue.

Dew shield: Slows the formation of dew on the lens in cold weather to extend your undisturbed observing time. Also improves visual and photographic contrast by shielding the lens from off-axis ambient light (the neighbor's yard light, moonlight, etc.)

Rack and pinion focuser: 2" focuser, with 1.25" eyepiece adapter. 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. The eyepiece holder has built-in T-threads for attaching an optional T-ring and camera for prime focus photography.

Star diagonal: 90° viewing angle prism-type 1.25" star diagonal.

Eyepiece: Fully multicoated low power 1.25" 25mm (40x) eyepiece with a 1.25° field of view (two and a half 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.

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 link in the support tab 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 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.

What can you see through this 120mm Celestron refractor?

With a relatively short 1000mm focal length and a light grasp 294 times that of the sharpest dark-adapted eye, the scope is capable of producing surprisingly bright wide-field images of the faint fuzzies outside the solar system - nebulas, galaxies, open star clusters, and more.

But those objects requiring high power and high contrast - globular clusters, close binary star pairs, lunar and planetary images, etc. - are where this achromatic scope shines. Using optional eyepieces and/or a Barlow to boost the magnification, you can see subtle solar system details that are virtually invisible in smaller aperture scopes. You can study 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. Chromatic aberration (a faint halo of spurious violet light around very bright objects, such as the planets) is present, as it is in all achromatic refractor telescopes, but is generally unobjectionable and is not a problem on the faint objects outside the solar system. Using the lens cap/aperture stop mentioned above will reduce its visibility. The use of an optional aberration-reducing minus violet filter will also help eliminate the spurious color (which many people find unobjectionable in any case).

Optically and mechanically refined, and very reasonable in cost for a big 4.7" aperture refractor, this Celestron Omni XLT 120 has enough optical performance to keep you busy for the rest of your life.

Tech Details

Aperture 4.7"
Focal Length 1000mm
Focal Ratio f/8.3
Heaviest Single Component 21 lbs.
Highest Useful Magnification 250x
Motorized Controls Optional Motor Drive Is Available
Weight 46 lbs.
Resolution 0.97 arc seconds
Supplied Eyepiece 25mm 1.25"
Telescope Type Refractor
View Finder 6x30
Visual Limiting Magnitude 12.9
Warranty 2 years


Review by:
I bought this telescope for two reasons: I wanted a refractor to complement my reflector, and I was not pleased with the views of planets with the reflector, so I wanted to try a refractor. I'm very happy with the Celestron Omni XLT 120. It is light enough to be easy to move, set up and break down. The optics are great; minimal chromatic aberration, with very good focus. The rack and pinion focuser is smooth, with no noticeable backlash. I'm not using the Celestron mount, I use my Orion Skyview Pro that came with my 8" reflector. I also upgraded the 1.25" Celestron star diagonal with a 2" GSO dielectric diagonal, and I replaced the Celestron finder with a 9X50 right angle finder and laser pointer.
I'm very happy with the telescope. The views of planets are better than the reflector, but still not what I was hoping for. I think much of my viewing trouble is due to the excess light pollution where I live. (Posted on 10/31/2019)
Review by:
My XLT120 is my "grab and go" scope for star parties. Hundreds of people have viewed the planets through it and none have complained of CA. Great, crisp views with a smooth focuser. I use a zoom 8 - 24 eyepiece and get beautiful resolution at 125x. Highly recommend as a first scope or grab and go for the more seasoned. (Posted on 7/29/2019)
Review by:
Good scope, lightweight tripod is stable. Drive motor is optional. (Posted on 10/16/2018)
Review by:
Celestron has made an excellent telescope for anyone interested in beginning in observational astronomy with instruments. The scope has the right balance for easiness to use and the necessary learning for a beginner. Also, it give an useful aperture for a vast list of objects, including DSOs. What you will see are crisps views, nonetheless being a achromatic, which will become apparent just with the most bright objects, that would be planets and the Moon. So, for the price, the scope is more than alright, and its quality is more than enough for years to come. I´ve mine since 2008 and I´m very satisfied. (Posted on 10/8/2018)
Review by:
This was my first telescope I ever purchased, and it was a beaut. It rides on the CG4 mount which I have recommended to every new beginner for visual use only if their OTA could handle it. The scope itself put up marvelous views with CA on the brighter planets on the moon. If CA truly bothers you, then this wouldn't be the scope for you. If CA is no concern or bother like it is me, this is a great visual combo buy. A very nice feature is if it arrives out of collimation you have the opportunity to bring it back in with the push-pull screws. I replaced the OTA with an ED scope, but liked it so much I gave the OTA to my dad rather than sell it. Highly recommend (Posted on 10/6/2018)
Review by:
Celestron Omni XLT 120
Views of the moon and planets are excellent with this 120mm / 4.7-inch achromatic telescope and I can use 300x on a night when the seeing is good and steady. The XLT120 is capable of good deep sky work, especially double stars. The fit and finish are first-rate; when considering the price the build quality of this scope is excellent. The views are sharp and very contrasty, however a light yellow filter will help a lot on any false color. Jupiter has a slight halo around it with out a filter but that does not in any way detract from the viewing experience one iota. This scope works quite well for solar viewing in fact the addition of a solar filter will increase the utility of the XLT120 immensely. The rack and pinion focuser is adequate, however it will be my first upgrade. I would like to see Celestron support this scope with a bit heaver mount, but this mount and scope are well worth the price. I would recommend it to a friend. (Posted on 8/4/2017)
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Supplied Accessories

  • Fully Starbright XLT multicoated 120mm aperture 1000mm focal length f/8.3 achromatic optics
  • 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
  • 2" rack and pinion focuser with 1.25" eyepiece adapter
  • 1.25" prism-type 90° star diagonal
  • 1.25" 25mm eyepiece (40x)
  • Dewcap
  • Dust covers
  • Two-year warranty.