SkyWatcher Telescope Dobson Reflector 16" 406/1800 Extendable Dobson Reflector

SKYWATCHER TELESCOPE DOBSON REFLECTOR 16" 406/1800 EXTENDABLE.

The Sky-Watcher Dobson 16" extendable reflector telescope, 406 mm diameter and 1800 mm focal length, has a Pyrex parabolic primary mirror to eliminate spherical aberration and a very thin (0.5 mm thick) four-arm mount to support the secondary mirror avoiding the formation of diffraction spikes and light loss. In addition, these models include a 2" Crayford focuser with 1.25" adapter, allowing the use of any size eyepiece.

But what is a Dobson telescope? It is a very simple and elegant altazimuth mount design that was popularized by John Dobson in the late 1970s. Dobson's idea is very popular with amateur astronomers and telescope manufacturers because of its simplicity. In its simplest form, the Dobson mount consists of a box that makes it possible to mount the optical tube to pivot in altitude, while the box itself can rotate on an azimuthal base. These types of mounts generally rely on friction between the side bearings on the optical telescope tube and a friction material on the mount to hold the optical tube in place. If there is too much friction, it is difficult to move the telescope to center an object in the field of view. Conversely, if there is too little friction, the telescope will not be stabilized. This makes stabilizing the optical tube difficult when accessories, such as a finder, camera or eyepiece, are added to the telescope.

As long as the amount of friction is adequate, and therefore stabilization of the optical tube is achieved, the telescope can remain in the desired position for observing an object and maintain its position even when the mount is rotated. Devices for stabilization of a Dobson system telescope currently include: a shiftable weight for proper counterbalancing of the telescope, a friction lock that must be adjusted to inhibit telescope movement, and a spring connected between the telescope tube and the mount to aid in stabilization.

These devices do not provide a simple, user-friendly way to adjust friction. Therefore, Sky-Watcher's improved Dobson telescopes are equipped with a Tension Control Handle by which users can easily control the tension applied to the assembly to add or reduce friction. With this novel system the telescope does not need to be balanced in order to remain in position. This tension adjuster can be tightened in such a way that the optical tube can remain in one position, but still move when requested to adjust the position of the telescope. Alternatively, the tension adjuster can be tightened completely to lock the tube securely.

The exciting new Dobson Sky-Watcher series of reflecting telescopes features a new generation of precision-engineered instruments that will allow you to view the treasures of the night sky such as planets, nebulae, star clusters, galaxies and much more. With their patented folding tube design, these Dobson's are truly the ultimate in portability and performance and are absolutely spectacular for their superb focal to brightness ratio in deep sky observing.

Their sleek, extendable frame design has been carefully studied to combine ease of use, extreme portability and consistent performance in an affordable package for advanced amateurs. Unlike other Dobson telescope designs, this SkyWatcher folding mount does not need to be disassembled between uses. It is transported as two compact pieces that can be assembled ready for observing in a matter of seconds. It is easy to collimate once the telescope is installed, maintaining its collimation throughout the night.

TECHNICAL CHARACTERISTICS:

• • Objective diameter: 406 mm
  • Focal length: 1800 mm
  • Focal ratio: f/4.4
  • Optical design: parabolic Newton reflector made of Pyrex
  • Focuser: Crayford 2 " focuser
  • 2" to 1.25" adapter
  • SP series 10 mm and 25 mm 1.25" Eyepieces magnification: x180, x72, x180, x72 respectively
  • Theoretical maximum magnification: x812
  • Stellar magnitude limit: 15
  • 8 x 50" finder
  • Extendable Dobson mount with new pressure adjustment system
  • Secondary mirror diameter: 100 mm
  • Tube weight: 38 kg
  • Tube length: 168.5 cm

SKYWATCHER TELESCOPE REFLECTOR DOBSON 16" 406/1800 EXTENDABLE.