Sky watcher skymax 127 127mm 5 f1500 maksutov cassegrain optical tube assembly skymax black diamond series maksutov cassegrains available in apertures of 127mm 150mm and 180mm excel for high power high resolution and planetary applications they employ super high contrast optical systems utilising high transmission multi coatings on all optical services for optimum optical performance the quality of each telescope is monitored by means of a ronchi test and an artificial star test n