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What Does a Telescope Eyepiece Lens Do?

Telescope eyepieces are used with telescopes to magnify faraway objects. Eyepieces are placed where the telescope optics have focused the image, either at the end of the telescope, for refractors, or on the tube, for reflector telescopes.

Types of Eyepieces
- Telescope eyepieces
  
  Telescope eyepieces come in different barrel diameters to fit different telescopes. They also come in different lens designs created with different purposes in mind.
Lens Designs
- Lenses have inherent problems including optical distortions or chromatic aberration, where colors are shifted. In telescope eyepieces, various lens types have been put together to correct these distortions and/or aberrations.
Magnification
- The magnification of an eyepiece is the focal length of the telescope divided by the focal length of the eyepiece. A telescope with a focal length of 1000 mm and an eyepiece with a focal length of 25 mm results in a magnification of 40.
Field of View
- The field of view is the area you can see with your eye through the eyepiece. The higher the magnification the lower, or narrower, the field of view.
Eyes on the Sky
- Eyepieces allow for exploration of our nighttime skies. Careful selection of eyepieces allows for the best astronomical viewing opportunities.

Astronomy