The Best Refracting Telescope for Beginners
Celestron Omni XLT 102 Refractor
Celestron Omni XLT
- 102 102mm f/9.8 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)
- Best place to buy: Amazon
- My Rating: 4.5 out of 5
Celestron Omni XLT 102 is definitely my favorite for the best refracting telescope for beginners. The combination of high-quality optics and solid German equatorial mount provide excellent performance, portability, stability and features that any astronomer would appreciate.
If you are among those who like to watch objects in the Solar System and those in deep space as well, Celestron Omni XLT 102 has a lot to offer.
Extremely good telescope for observations within the solar system! With its clear and sharp images of lunar and planetary details you will not be able to detach from eyepiece for hours.
Relatively large aperture and diffraction-free images contribute to surprisingly good results with observations in deep space. Binary stars and globular star clusters are especially well-resolved. The telescope is also dealing well with nebulas and galaxies- something which is generally possible with comparably expensive reflector telescopes.
Refractor optics: 4” (102mm) aperture, 1000mm focal length, f/9.8 achromatic doublet lens using aspheric shaping technology for images that have virtually no spherical aberration. The lens cell is fully collimatable for optimum sharpness. The optical tube length is a very manageable 39.5”.
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.
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.
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 rings are connected to a mounting plate that 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.
With a relatively short 1000mm focal length and a light grasp 212 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 is present in the scope when viewing very bright objects, as it is in all achromatic refractor telescopes, but using the lens cap/aperture stop mentioned above will reduce its visibility.
Optically and mechanically refined, and very reasonable in cost for a 4” refractor, this Celestron Omni XLT 102 has enough optical performance to keep you busy for the rest of your life.
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Alternative sizes: Omni 120mm Omni 150mm
|Aperture (mm)||102 mm (4.02 in)|
|Focal Length||1000 mm (39 in)|
|Focal Length of Eyepiece 1 (mm)||25 mm (0.98 in)|
|Magnification of Eyepiece 1||40 x|
|Mount Info:||Adjustable height tripod|
|Mount Type||Omni CG-4 Equatorial|
|Tripod Leg Diameter||1.75″ Stainless|
|Highest Useful Magnification||241 x|
|Lowest Useful Magnification||15 x|
|Limiting Stellar Magnitude||12.5|
|Resolution (Rayleigh)||1.37 arc seconds|
|Resolution (Dawes)||1.14 arc seconds|
|Light Gathering Power (Compared to human eye)||212 x|
|Apparent Field of View||1.25 °|
|Linear Field of View (@1000 yds)||66 ft (20 m)|
|Optical Coatings||StarBright XLT|
|Optical Tube Length||39.5 in (1003 mm)|
|Optical Tube Weight||9.5 lbs (4.31 kg)|
|Tripod Weight||12.5 lbs (5.67 kg)|
|Weight of Counterweights||7 lbs (3.2 kg) and 4 lbs (1.8 kg)|