Sky watcher skyliner 400p flextube 406mm 16 f1800 parabolic dobsonian telescope sky watcher patented flextube range of truss tube dobsonian models all feature collapsible otas making them incredibly easy to transport and store offering the ultimate flexibility for owning an otherwise large telescope they all feature 2 part telescope tubes attached with 3 arm supports when in use the tube is fully extended and each arms axis is clamped to ensure a rigid perfectly collimated high perf