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This Sky-Watcher PRO 120ED apochromatic refractor has:
• 120mm f/7.5 apochromatic doublet optics using Schott glass and an FPL53- ED element
• dual-speed 2" Crayford focuser with 10:1 ratio fine focusing
• 2" dielectric star diagonal with 2" and 1.25" eyepiece holders
• two 1.25" Long Eye Relief eyepieces (20mm and 5mm)
• 8 x 50mm right-angle finderscope
• dovetail shoe for installing on a Celestron CG-5 mount or any Vixen-style altazimuth or German equatorial mount
• two-year warranty
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The Sky-Watcher PRO 120ED from Celestron was named Sky & Telescope Hot Product for 2010. In an October 2009 review of the PRO 120ED, Sky & Telescope said, “the Holy Grail of any refractor, and one expected of a scope carrying the apo moniker, is an in-focus star image free of false color fringes. The SW 120ED easily passed that test, but even when its images were slightly out of focus they remained free of obvious color fringing. As such, stars that danced around in turbulent seeing remained pure in color, which is not always the case for apos that are color-free only when precisely focused . . . Don't be fooled by its modest cost; this 120-mm apo delivers images that are on par with premium-priced instruments . . . Its performance as a visual telescope was on par with similar-size apo refractors costing three times as much." Sky & Tel concluded in the “At-A-Glance" section of their review: “What We Like: excellent optics; handsome appearance. What We Didn’t Like: nothing."
The Sky-Watcher PRO 120ED uses a crown glass element of premium Schott Glass, an FPL-53 ED glass element, and state-of-the-art optical multicoatings in its apochromatic ED doublet optics. The result is images that are essentially free of the annoying halo of unfocused violet light (chromatic aberration) that often mars the view of bright stars and solar system objects in other large aperture doublet refractors that only use an FPL-51 ED element in their optical system. In addition, there is no loss in contrast such as you will find in reflector and catadioptric scopes that have a secondary or diagonal mirror hanging in the light path to scatter light..
The 120mm Sky-Watcher doublet optics are even more appealing when you consider that this Sky-Watcher apo is loaded with features other manufacturers charge extra for (or don’t even have available) – such as an 8 x 50mm right-angle finderscope, a 2" dielectric star diagonal with 1.25" and 2" compression ring accessory holders, two 1.25" LE (Long Eye Relief) eyepieces (LE20mm and LE5mm); and a foam-lined aluminum-clad carrying case.
The Sky-Watcher PRO 120ED has enough premium high contrast/high resolution optical performance to let you use it as the heart of your observing system. With a weight of 11.3 pounds, it will work well on most medium duty equatorial mounts, but may start to push the capacity of some altazimuth mounts. That said, the Sky-Watcher 120ED is still light enough to take out and set up for observing on very short notice. Considering its surprisingly low price for an apochromatic doublet, adding in the extra features you get at no extra cost, and in view of the great optical performance that comes as standard equipment, the 120mm Sky-Watcher PRO 120ED is a terrific buy!
Features of this telescope . . . - Apochromatic ED doublet refractor optics: 120mm (4.72") aperture, 900mm focal length, f/7.5 focal ratio. The optics use a crown glass front element of premium Schott Glass, from one of the world’s most-respected glass manufacturers. The ED element is precision-polished from high grade FPL-53 ED (Extra-low Dispersion) glass. This ED element produces superior sharpness and color correction by minimizing the chromatic aberration, the “false" color fringing seen around bright objects when light rays pass through standard crown-and-flint doublet objectives. The result is to reduce spurious color halos and fringing to vanishingly low levels.
- Fully multicoated optics: Each air-to-glass surface in the Sky-Watcher PRO 120ED doublet objective lens has MHC (Metallic High-Transmission Coating) antireflection multicoatings on all air-to-glass surfaces for high light transmission, minimal light scatter, and excellent contrast.
- Internal light baffles: Contrast-enhancing internal light baffles in the tube and focuser drawtube and a specially darkened tube interior provide dark sky backgrounds and high terrestrial contrast.
- Dew shield: The supplied dew shield slows the formation of dew on the lens in cold weather to extend your undisturbed observing time. It also improves the contrast, similar to the effect of the lens shade on a camera lens, when observing during the day or when there is excessive ambient light at night, such as a neighbor’s backyard security light. The substantial 11. 3 pound optical tube measures 37.8" long, including the dew shield. A slip-on metal dust cap is standard.
- Dual speed 2" Crayford focuser: The precision-made no-backlash focuser has dual-speed focusing. There are two coarse focusing knobs. The right knob also has a smaller concentric knob with 10:1 reduction gear microfine focusing. This provides exceptionally precise image control during high magnification visual observing and critical DSLR or CCD imaging. The large focus knobs have ribbed gripping surfaces so they are easy to operate, even while wearing gloves or mittens in cold weather. Lock knobs lets you adjust the tension on the drawtube to accommodate varying eyepiece/photo accessory loads, as well as firmly lock in a photographic focus.
- 2" dielectric star diagonal: The supplied standard equipment 2" mirror star diagonal of the PRO 120ED slips into the focuser drawtube’s 2" eyepiece/accessory holder. The 2" diagonal has 99% reflectivity dielectric mirror coatings for high light transmission. A supplied 1.25" accessory adapter slips into the 2" diagonal to let you also use 1.25" eyepieces. The 1.25" accessory adapter can also be inserted directly into the 2" accessory holder on the focuser drawtube to let you use a 1.25" image erecting diagonal, or 1.25" photographic accessories.
- Supplied eyepieces: Two 1.25" long eye relief eyepieces are supplied as standard equipment – a 20mm (45x) and a 5mm (180x).
- Finderscope: The Sky-Watcher PRO 120ED comes with an 8 x 50mm right-angle finderscope that is fully-multicoated to insure maximum brightness and contrast.
- Mounting dovetail: The Sky-Watcher PRO 120ED apo from Celestron has dual hinged split-ring tube rings and a dovetail mounting bar that fits directly into the Vixen-style dovetail slot on the head of many of the most popular medium capacity altazimuth and German equatorial mounts. Such mounts include the Astro-Tech Voyager altazimuth, the Celestron CG-5 Advanced Series go-to equatorial, the Meade LXD-75 go-to equatorial, and the Vixen Sphinx and Great Polaris Deluxe equatorial mounts, among others.
- Shipping/storage case: The scope comes in foam-fitted aluminum-clad shipping/storage case.
- Two-year warranty: The Sky-Watcher PRO 120ED doublet apo from Celestron is protected by a two-year limited warranty against flaws in materials and workmanship.
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