All about Dobsonian Sky-Watcher FlexTube 203mm f/6

In recent years, Dobson fever has increasingly invaded amateur astronomers aware that the strongest sensations are felt with large diameter telescopes. The observation of the planets is indeed limited to Jupiter, Mars, Saturn (and the Moon) while the clusters, nebulae and galaxies are counted by the hundreds in a 200mm instrument (see thousands for the largest diameters under a dark sky) . Without motors or electronics, Dobsonians are indeed the instruments providing the most light, at a given budget, compared to any other type of instrument (mostly motorized and Go-To).

A Dobsonian but compact

However, the quest for diameter generates a major inconvenience: the size! When you want to observe in the best conditions, to exploit the full potential of your instrument, far from the light of cities, it is imperative to move your equipment in a vehicle then to assemble and disassemble it. However, space is needed and, if possible, a minimum of comings and goings during loading. Although Serrurier structures have been around for a long time, they have only recently been available on inexpensive Dobsonians and require permanent dismantling/reassembly and then re-collimation (an operation that takes a little time but which you eventually get used to with experience).

A telescopic telescope

Sky-Watcher, which has been designing solid-tube Dobsonians that have been popular with beginners and amateurs for many years, innovated in 2009 by completely adopting the design of its instruments. The Sino-Canadian manufacturer has sought to combine the advantage of "complete assembly" of solid tubes and the small size provided by open tubes. The idea of ​​the "telescopic telescope" is now a reality (at a price that remains very attractive) through the FlexTube range.

According to the principle that "the best instrument is the one used most often" SkyWatcher pushes comfort further with the FlexTube range so that you do not hesitate for a moment to contemplate the sky and its wonders.

FlexTube: ultimate comfort

The principle of the FlexTube is simple, it is based on a locksmith type design, where 3 tubes solidly support the secondary mirror cage (which also supports the focuser and the finderscope). Except that here the tubes are not removable because they are housed in a clamp that allows them to slide. By simply loosening 3 knobs, the tubes slide down until the instrument is folded. Three screws on the secondary cage then lock it to the primary body. The set is much "smaller" easily fitting, vertically, in any car trunk (maximum height of 920mm for the 305mm). With a 630x740mm base you will even have room for various accessories.

The important point of such a configuration is the behavior of the collimation (alignment between the 2 mirrors). According to the manufacturer, the FlexTube retain the positioning of the 2 optical elements (particularly the secondary mirror) at each folding/unfolding. Note: the alignment does not change during the night or according to the position of the optical tube. There is therefore nothing easier than setting up such instruments. Take out the complete telescope using the handles (altitude tightening knobs) (40kg in total for the largest model). Loosen the tube tightening knobs (as well as the locking screws). Slide the mirror cage to the stop position of the tubes. Tighten the knobs to finish.

As there is no need to set up, your telescope is ready for an evening of observation full of discoveries (if you haven't touched the focuser since your last outing, then the focuser will already be "ready "). In just a few seconds you will have completed/avoided the traditional steps: telescope exit / assembly / collimation. Save more time and enjoy unparalleled comfort!

Version with GoTo (automatic pointing)

To offer more comfort to the user, Sky-Watcher has decided to equip its range of Dobsonians with a dual-axis motorization (equivalent to a motorized altazimuth mount) with a hand control capable of pointing and followed. So there is no need to know the position of stars or distant stars in the deep sky, the Dobsonian mount AZ GOTO takes care of moving the instrument towards the target you want to observe.

After calibration (setting up), orientation of the optical tube to North and leveling, select the alignment of the mount on one, two stars. More than 42,900 objects including the main catalogs are recorded in the database (Messier, NGC, IC as well as the planets, the Moon and the Sun). For maximum comfort the mount moves quickly via the SynScan hand control. Simple to use, it helps to quickly direct the instrument to any galaxies, nebulae, clusters or objects in the solar system. Discover in detail the famous Andromeda galaxy, the fabulous draperies surrounding the heart of Orion, the cluster of Hercules M13 and its heart rich in thousands of stars. Saturn, Jupiter and the Moon are also marvels to scrutinize without moderation.


The date, time and observation location indication in the controller combined with the "Tour" function allows the AZ GOTO to be pointed at the most interesting objects throughout the evening. Treat yourself to a guided tour of the sky of your place of observation by clicking on the "Enter" button according to the object presented in a drop-down list. The ability to track any object avoids having to systematically perform manual overhauls (useful during observation evenings with the general public). The object remains in the center of the field, it then becomes easier to discover details in particular on the planets.

Now the Sky-Watcher FlexTube GoTo range includes an integrated WiFi card that allows you to control the telescope remotely with your smartphone or tablet, without any connection cables, using the free SynScan Pro application (iOS / Android) :

https://play.google.com/store/apps/details?id=com.skywatcher.synscanapppro&gl=FR.

Items Delivered

•         1 Newton FlexTube Sky-Watcher 203mm f/6 optical tube
•         1 Dobsonian azimuth mount
•         2 flowing eyepieces 31.75mm: Super 10mm and Super 25mm
•         1 straight finder 9x50
•         User manual in French