TUBE (QUATTRO 200 ST):
Fast focal ratio of f/4.
Black Diamond P200/F800 Reflector. This is especially important for astro-photographers dealing with long exposure times. Imaging telescopes made of less thermally stable material can deviate from optimum focus after long time exposures. It can remain in focus for a longer period of time and long exposure images will stay clear and in focus.   Tube interiors are equipped with knife-edge ray traced baffles. 

2" DUAL-SPEED LINEAR POWER FOCUSER (both models): The new linear power focuser utilises 4 precision ball bearings to support the drawtube and provide great stability and zero image shift while supporting a heavy eyepiece or camera. Moving the drawtubeby the roller rather than a rack and pinion ensures exceptionally smooth operation, great feel and precise adjustability. The dual-speed feature has a second focus knob that has a 10:1 speed reduction to provide the super-fine adjustments even the most demanding users can appreciate.  

PYREX MIRRORS: Both models feature paraboloidal primary mirrors made of low thermal expansion Pyrex glass resulting in substantially shorter cooling-down times.

 It comes with a impressive 0.5 mm Ultra-Thin Secondary Mirror Support and it is 77% more Light-Gathering than 150mm.