All about the Newton Sky-Watcher 200mm f / 4
SkyWatcher has designed this tube for astrophotographers with a faster focal ratio f4 in order to offer better performance in deep sky images, a wider field and a much higher photographic speed for the same exposure time. A shorter focal length ratio allows you to obtain more signal or with an equivalent signal, reduce the exposure time. In addition, the size of the tube is reduced, which also means less wind resistance.
With a 200mm primary mirror of parabolic construction, the Sky-Watcher Newton 200 collects 78% more light than a 150mm telescope. Under a very dark sky it is possible to see many objects in the sky that are barely visible on instruments of smaller diameter. It promises beginners and astronomers many years of discoveries. In planetary observation, you will reveal many details about Jupiter, Saturn and the Moon using a Barlow lens or a short focal length eyepiece.
Its Newton design offers several advantages over other families of instruments (refractors and retro-reflectors). Mirror manufacturing is cheaper for the same diameter and its medium focal length (800mm) is very versatile. You will also benefit from an attractive budget with a bright telescope that provides a diverse field of observations. The central obstruction is also lower than Cassegrain-type telescopes.
Unlike the cheaper manufacturers or small diameter Newtons, the 150, 200, 254 and 300mm Newton Sky-Watchers have a parabolic primary mirror. The mirrors are spherically polished and then re-cut to a paraboloidal shape (more expensive and difficult to obtain). It is an essential choice criterion for instruments above 130mm and short focal ratio.
Focus is obtained through a Crayford double speed eyepiece holder. Allows you to get a fine focus thanks to the 1:10 ratio. A very noticeable advantage during high magnification observations and imaging. Allows to support heavy loads (ex: APN). A 31.75mm adapter is supplied as standard to use eyepieces of the same format from the 50.8mm exit. An adjustment screw located at the bottom of the eyepiece holder maintains focus according to the orientation of the optical tube.
To present the least possible obstruction, the secondary (flat) mirror fixation bracket has 4 thin branches, 0.5 mm wide. Rigid enough, they thus limit diffraction peaks in bright stars and excessive loss of luminosity. A 9x50 achromatic finder is also supplied as standard on its stand.
Optical Design Reflector
Optical Diameter 205 mm
Focal Length 800 mm
Highest Practical Power 410x
Finder Scope 8x50
Focuser Diameter 2" (50.8mm) Dual-Speed 10:1 Linear Power Focuser
Tube Weight 9.5 kg
Tube Dimensions 23.5cmx71.1cm
Shipping Weight 12.7 kg
Shipping Dimensions 80x40x44 cm3
1 Sky-Watcher 200mm f / 4 optical tube
1 x Crayford Sky-Watcher 50.8mm focuser with micro focuser (1:10 dual speed) and 31.75mm adapter
1 reinforced Vixen dovetail
1 Kodak camera overlay bracket on top of one of the mounting clips
1 straight 9x50 finder scope