# Eyepiece

Also called: ocular, Plössl, wide-angle eyepiece.

The small lens you look through, which magnifies the telescope's image; its focal length sets the power.

Eyepieces are interchangeable: shorter focal lengths give higher [magnification](https://astropilot.space/glossary/magnification). Besides focal length, two things matter: the [apparent field of view](https://astropilot.space/glossary/apparent-field) (how wide the view looks — 50° in a Plössl, 82–100° in ultra-wides) and [eye relief](https://astropilot.space/glossary/eye-relief) (how far your eye sits from the lens).

They come in 1.25″ and 2″ barrels; the widest low-power fields need 2″ eyepieces.

**At the eyepiece:** A good kit covers low, medium and high power with a step of about 1.5× between eyepieces.

**In AstroPilot:** Add your eyepieces under My gear: AstroPilot shows their magnification, exit pupil and field on each telescope, and which to use for each object.

**Related:** [Magnification](https://astropilot.space/glossary/magnification.md), [Apparent field of view](https://astropilot.space/glossary/apparent-field.md), [True field of view](https://astropilot.space/glossary/true-field.md), [Eye relief](https://astropilot.space/glossary/eye-relief.md), [Barlow lens](https://astropilot.space/glossary/barlow.md)

From the AstroPilot astronomy glossary: https://astropilot.space/glossary/eyepiece