All about the Sky-Watcher Black Diamond 120ED telescope
Sky-Watcher renewed its range of instruments a few years ago by modifying the design and some mechanical elements. The series called Black Diamond, includes Dobsons, Refractors, Newton and Maksutov. As for the telescopes, the "classic" diameters are maintained: 80, 100 and 120 mm, except for a change in color (black with white inlays). Only the 50.8mm Crayford focuser has been changed. The renowned optical quality of the 120ED Sky-Watcher offers everyone the ability to purchase a powerful instrument at a very attractive price for wide field astrophotography or planetary and solar observation. A 120mm telescope collects 2.25 times more light compared to an 80mm refractor
To obtain the valuable "APO" qualifier, a refractor must correct for primary and secondary chromatic aberrations inherent in all systems whose light rays pass through an optical element. In the case of the Sky-Watcher Black Diamond 120ED, a doublet composed of an ED glass element reduces chromatism to significantly limit the appearance of colored edges on the planets or the Moon. The ED glass chosen, FPL-53 (Schott), is the most capable of correcting these defects thanks to a very low dispersion. Thanks to its medium focal length ratio, f / 9, the Sky-Watcher Black Diamond 120ED is particularly interesting for deep sky and planetary photography.
The use of multilayer treatments on all surfaces considerably limits losses due to lens passage, making Black Diamond 120ED brighter and more contrasting than conventional refractors that are less corrected. The "Metallic High-Transmission" (MHC) treatment is applied to the air glass surfaces, which guarantees impressive results (transmission close to 99.5%). Thanks to its very short focal length ratio, f / 7.5, the Sky-Watcher Black Diamond 120ED is particularly interesting for deep-sky photography .
10: 1 double speed focuser
Focusing is achieved through a 2 "(aluminum) Crayford focuser with a fine focus knob with 10: 1 reduction ratio, which provides the necessary force and precision when focusing. An adjusting screw maintains the focus depending on the optical orientation of the tube to be aligned with the objects and provide good results in astrophotography (where focus is essential).
To meet the requirements of amateur astronomers, the optical tube is made entirely of steel. Plastic parts are not used! The solidity is and the aesthetics are in tune. The interior is blackened and manufactured to limit stray light intrusion.. A Kodak through screw is placed over one of the clamps to parallel adapt a camera.
Optical Design ED Apochromatic Refractor
Optical Diameter 120mm
Focal Length 900mm
Highest Practical Power 240x
Faintest Steller Magnitude 13.1
Finder Scope 8X50
Focuser Diameter 2" dual speed, crayford
Diagnol 2" 90 deg. Dielectric Diagonal with 1.25" adapter
Eyepieces LET 2"-28
Tube Weight 5.13kg
Tube Dimensions 10 cm x 62cm
Shipping Weight 18 kg
Shipping Dimensions 120x45x46 cm3
1 Sky-Watcher Black Diamond 120ED optical tube
1 Vixen-type dovetail
1 x 50.8mm Sky-Watcher Eyepiece: 28mm LET
1 dielectric diagonal 50.8 mm
1 straight finder 9x50
1 Kodak camera overlay bracket on top of one of the mounting clips
1 rigid carrying case