Easy to use, No Fuss, Grab-and-Go Telescope. The Sky-Watcher EVOSTAR 90/660 is a classic two-element, air-spaced, achromatic refractor. With its f/7.3 focal length it can be used to observe the Moon, planets and many deep sky objects. This versatile telescope, when fitted with an optional erect image diagonal (available separately) would provide an upright, fully corrected image, allowing the telescope to be used for terrestrial observing also. The well engineered and easy to use AZ PRONTO Alt-Azimuth mount provides excellent stability and precise control, via its slow motion cables, on both the horizontal (azimuth) and vertical (altitude) axes. A capable, easy to use telescope that is highly recommended for beginners, or for more experienced observers wanting a convenient grab and go telescope.