The ASTELE 150 is an excellent astronomical telescope for observing the heavens. Its optical design is Maksutov Cassegrain. Its diffraction limited optics are multi-coated and make it a great instrument for doing astrophotography as well, delivering pin-point images over a 35mm format.If you're looking for a telescope that's easy to setup and has superb optics, the ASTELE 150 is that and more. Ideal for the professional or advanced amateur.The ASTELE 150 uses U.S. standard 1.25" O.D.-sized eyepieces (hundreds are available).