with 31.7 mm opening - countless objects directly into your eyepiece With an opening of 31.7 mm this provides a bright picture. You can now also observe rather weak objects in the universe directly through the eyepiece. Or watch Saturn with his rings,including the famous Cassini Division. Or travel on with this for a few more years - to star clusters and hydrogen mists. Astronomical Mount - Hold objects in the field of view The has an astronomical mount. If you have an object in sight,you can easily balance the rotation of the earth with the slow motion controls. This means that objects can always stay in the center of the field of view. For s without this mount objects will be out of sight again. But not like this! Focus on the night sky,not on the . So you can watch very relaxed. Focal length: 650mm Tube length: 572 mm Star search: 6x30mm Total weight: 11.0 kg Lens diameter: 31.7 mm Lens coating: Multicoat paint Focus ratio: F5 Resolution: 0.89 s Border star: 12.3 Concentration: 345x Size: length 152 mm outer diameter 160 mm Viewfinder mirror: 6x30mm Accessories: two eyepieces Eyepiece: NPL20mm,PL6.3mm Weight: 13kg