Sky-Watcher high-performance ED-APO refractors offer premium optical performance for the discriminating amateur astronomer. Refractors are coveted for their superb contrast, high-definition, and coal-black sky background that make stars appear like diamonds embedded in black velvet. Sky-Watcher ED APO refractors utilize the most modern optical glasses and fabricating techniques to deliver the ultimate in high-fidelity astronomical imaging. Subtle details pop as never seen before in telescopes of lesser optical capability.
The additional aperture compared to a 100 mm diameter lens provides a dramatic increase in resolution and a heightened sense of seeing lunar and planetary surface phenomenon in seemingly 3-D high-definition.
The rugged Southern Highlands of the lunar surface are rich in craters. To the southeast, the famous crater Theophilus is 65 miles across. The raised triple-peaked central area is striking to observe in your Sky-Watcher 120ED telescope, with massive walls and a basin that is 14,000 thousand feet deep. One of the Moon's southernmost craters, Clavius, is a very large crater 145 miles across. It is located south of Tycho. In this same area you will find the craters Maginus and Longomotanus, which are also very worthy of exploration. To the north, the young crater Tycho dominates the southern lunar landscape. Named after the famous Danish astronomer, Tycho Brahe, it is a spectacular sight with very high-rimmed walls. North of Tycho, appearing brightly in a basin, is the famous Rupes Rect (the Straight Wall), an 800-foot mountain that is a must see for amateur astronomers. Your Sky-Watcher 120ED will show it clearly and sharply the way you want to see it. On the north end of Mare Nubium, almost on the lunar N-S and E-W center line, you'll find 3 craters grouped together: Arzachel, a young impact crater 60 miles across and 13,000 feet deep, shows a terraced structure and a system of channel-like narrow depressions in its basin called rilles. Nearby are Alphonsus, a 70 mile wide crater, and Ptolemaus, a prominent ancient crater 90 miles across with a heavily worn dark interior. The Earth's Moon offers a treasure trove of fascinating detail to explore with your SW 120ED-APO EQ5 PRO. We have only featured a relative few examples of what is available. The views you will experience are so clear and sharp it might just feel like a veritable space-walk.
The inner solar system presents the colorful rusty-red planet Mars. Mars is a challenge for amateur astronomers, but your Sky Watcher 120ED will show some very interesting detail. Olympus Mons, a volcanic crater 375 miles across and 16 miles high, is just one of the quests your capable SW120ED can tackle. Nirgal Vallis is a channel 600 miles long that responds well to the razor sharp contrast provided by the Sky-Watcher 120 ED telescope. The Grand Canyon of Mars, Valles Mariners, dwarfs that of our Earth's Grand Canyon, but it still requires superb optics to view, even though it is 150 miles wide and 4 miles deep. When prominent, the gleaming white polar cap is in stark contrast to the redish-orange surface landscape of the rest of the planet. The gas giant, Jupiter, displays its swirling equatorial bands in high-definition, with festoons and tonality within the bands. With regular observation you will be able to follow storms and disturbances cross the planet in the southern equatorial band. Saturn's storied surface phenomenon is simply stunning. View the rings and clearly see Cassini's Division and cloud belts across the equator.
Enjoy the hunt for double stars like Epsilon Lyrae, the double-double in Lyra, or, always a star party favorite, the beautiful double star Alberio, located in the tail of Cygnus the Swan, is sensational. Alberio appears like a gold sparkler, and its companion looks like a blue-green sparkler. It is a perfect object to view with your Sky-Watcher 120ED. Algol, an eclipsing variable star, sometimes called the Winking Eye fluctuates in brightness, and Aldebaran, a beautiful orange giant in the constellation of Taurus, are both delightful sights to view with the SW 120ED. Tight globular star clusters like M13 in Hercules appear like a beehive of crisp stellar pin points circling the central core when viewed with a good refractor like the Sky-Watcher 120ED. M92, also in the constellation of Hercules, is a very compact globular with a bright core. It is also a great object to view with the SW 120ED. The bright central cores of prominent nebulae can be seen and the brightest stars can be observed illuminating the glowing nebulosity which appears as ghostly apparitions.
The superb capabilities of the Sky-Watcher 120ED provide performance on a par with a reflector of perhaps up to 7" in diameter on lunar, planetary, double-stars, globular star clusters, even the brighter nebulae. These objects will stand out in bold relief contrasted against a very dark, velvet-black sky background. Many advanced amateur astronomers feel the ED APO experience is astronomy's richest. As an astrograph, the Sky-Watcher Pro 120ED APO performs superbly, delivering crisp, high-fidelity imaging of solar phenomena (with proper filters) planetary, lunar and aperture appropriate deep-space phenomenon.
In a given aperture size, refractors will always exhibit sharper images than other optical designs because the refractor concentrates more light into the central airy-disk and first diffraction rings. There is no diffraction pattern interference caused by a diagonal mirror or secondary mirror being suspended in the optical path (central obstruction) as is the case with reflectors.
Sky-Watcher ED-APO refractors provide the finest images obtainable - bar none - in their design class. If you are on a quest for the ultimate in pristine, near textbook-perfect astronomical imaging, look no further! Sky-Watcher ED apochromatic refractors deliver dramatic coal-back skies and faithful, contrast-rich views of planetary and deep-space phenomenon that are second to none. Sky-Watcher ED-APO refractors are the logical choice as an investment in advanced instrumentation for exceptional viewing or photography.
The Sky-Watcher ED APO optical design assures virtual elimination of secondary, residual false color normally present in 2-element achromatic lens designs using Crown and Flint glass. Sky-Watcher APO refractors utilize a second lens element made from the mineral fluorite instead of Flint glass. Fluorite, CaF2, is a halide with unique properties and a hardness of only four. It is an exotic and difficult material to fabricate into a lens. Hence the cost of manufacturing a fluorite lens is quite high compared to a Flint lens element, for instance.
Why fluorite? Fluorite's molecular properties have several distinct advantages. First, it has superior dispersion characteristics compared to pure silica-based glass. It functions as a high-index lens with very low dispersion. We use the term ED to signify Extra-low Dispersion. Fluorite also corrects well for spherical aberration. Sky-Watcher utilizes only the very finest available fluorite lens, FPL-53.
The Sky-Watcher 120ED also benefits from the inclusion of Schott glass for the positive front Crown element in the objective. Schott is the recognized world leader in glass utilized for precision optical lens systems, including medical instrumentation, and famous-brand camera lenses.
Each air-to-glass lens surface has exotic anti-reflection metallic coatings applied to ensure optimum light through-put. The proprietary Sky-Watcher Metallic High-Transmission Coatings (MHC) are the finest photon anti-rejection coatings in their class.
Every lens element is individually inspected for purity and absence of striae and other image-degrading imperfections. Every lens is pitched polished to exacting standards of optical fabrication and performance by highly skilled opticians utilizing state-of-the-art methodology and rigidly controlled optical testing procedures. The result is high-quality, diffraction-limited optics performing to the theoretical limits of their respective aperture sizes. All lenses are uniformly air-spaced in their cell housings.
The objective lens cell is light-baffled to reject stray, unfocused light. The draw tube is likewise baffled to insure optimum contrast. The tube interior is flat blackened to help prevent unfocused internal light reflections from reaching the focal plane.
Other Highlights of the Sky-Watcher 120ED Telescope...
- Optical focus is achieved by means of a mechanically ultra-smooth, backlash-free, precision 2" Crayford-style rack & pinion focuser-assembly. This focuser offers 2-speed fine and ultra-fine focusing adjustments.
- The optical tube material is aluminum, powder-coated reflective gloss black with gold fleck accent. The front and back cells are cast-aluminum painted white, or black.
- The telescope is supplied with a right-angle 9 x 50 mm viewfinder with bracket; a 2-inch dielectric diagonal; two 1.25-inch LE (Long Eye Relief) eyepieces (LE 20 mm and LE 5 mm); a 1.25-inch focuser adapter; tube ring attachment hardware for mounting to the Sky-Watcher EQ5PRO Mount (or other compatible mount), and a foam lined aluminum carry/storage case.