A fast focal ratio of f/4
This is especially important for astrophotographers 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
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 drawtube by the roller rather than a rack and pinion ensures exceptionally smooth operation 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.
It features paraboloidal primary mirrors made of Low-Expansion Borosilicate Glass resulting in substantially shorter cooling-down times.
It comes with an impressive 0.5 mm Ultra-Thin Secondary Mirror Supports and it offers 56% more Light-Gathering than the 200mm.