Celestron Nex Star

hits an aspherically shaped Schmidt correction plate and is further reflected onto the spherical primary mirror. This reflects it onto a secondary mirror, which reflects it back towards the main mirror. The light beam now passes the main mirror again, which has a central hole. Thus the light is thrown into the eyepiece extension located at the lower end of the tube. The system is thus closed and does not suffer from air turbulence which could deteriorate the image. Of course, this also provides optimum dust protection. The Schmidt plate is multi-coated, which ensures bright and low-reflection images.

These optics offer a very good image, contrast and sharpness convince and offer great fun in planetary observation. The Schmidt-Cassegrain System is a good all-round instrument for observation and photography with a huge range of optional accessories. The view at the lower end of the tube allows easy orientation. The telescope can also be used for occasional earth observations (e.g. at close range for bird watching). The Celestron SC optics are designed for an aperture ratio of about 1:10, so astrophotography is still possible.

The main mirror focusing ensures a very wide focus range, which makes it possible to adapt almost any accessory. In the positioning mechanism for focusing the main mirror two preloaded ball bearings are used to minimize "mirror shifting" (a typical problem when using simple bearing bushes). The use of high quality materials such as CNC milled components made of aluminium, cast steel and stainless steel ensures high stability at low weight, so no very heavy mounting is needed, which may be necessary with other optical designs.