An eyepiece is a crucial component of optical instruments like telescopes and microscopes. It is the lens or set of lenses through which a user looks to magnify and view an object. Eyepieces come in various designs and magnification levels, allowing users to adjust their viewing experience based on the specific needs of their observation. In addition to magnification, eyepieces can also affect the field of view and eye relief, which is the distance from the eyepiece where the user can comfortably see the entire image. Different types of eyepieces, such as Plössl or Kellner, offer unique advantages for different applications in science and astronomy.