The part of the telescope that actually magnifies the image. Using different focal length eyepieces will change the resulting magnification of the telescope. Typically, an observer will own several eyepieces in order to accommodate a variety of different viewing situations. Eyepieces usually consist of three or more lens elements. A wide variety of designs, each with their own characteristics, are available.
If you need some advice to select your eyepiece's focal length, try out this calculator. This calculator was kindly supplied by Johan Smit of the Pretoria Branch of ASSA.
