Eyepieces
Eyepieces determine the magnification and field of view of a telescope. Different eyepieces are used to view different objects. Some objects, such as nebulae and star clusters, appear quite large and are best viewed at low magnifications (which give a wider field of view), whereas planets appear very small and are normally viewed with high-magnification eyepieces. One of the most common misconceptions in amateur astronomy is that magnification is the most important aspect of a telescope. In reality, the diameter (aperture) of a telescope determines its power and different eyepieces are used to get the best view of a given object. Often the best view is at a low magnification.