Sky-Watcher Explorer 250PDS NEQ6 PRO

PARABOLIC PRIMARY MIRRORS
Features High Quality Parabolic Primary Mirrors to eliminate spherical aberrations inherent in ‘fast’ focal lengh reflectors with spherical primary mirrors. The mirrors are parabolized to bring all the light rays to the same focal point to give sharp, constrasty images, which are full of detail.

SKY-WATCHER DELUXE MIRROR COATINGS
Most reflectors today usually have a coat of aluminium as the mirror surface and then an overcoat of silicon monoxide or silicon dioxide to protect it. Silicon dioxide produces a much more durable coat than silicon monoxide but requires specialized equipment to apply it and is therefore more expensive. Protection is needed, because in most reflectors, the mirror is open to the elements and deterioration of the reflective layer reduces the resolution of the telescope.ALL Sky-Watcher reflectors are Multi-Coated with Silicon Dioxide as standard for Optimum Durability and Long Term Performance.