Introduction

How many times have you bought an eyepiece? Chances are you're still using the budget models supplied with your telescope. What isn't readily appreciated by a great deal of observers is just how important good eyepieces are to scope performance. An instrument can possess the finest objective lens or mirror, but the exquisite detail at its focus will not be faithfully conveyed to the eye or camera unless an eyepiece of equal quality is used. It may seem like a small link in the chain, but it can make or break the optical system. When a cheap eyepiece is replaced with a quality one, observers are often astounded, to the extent that they feel as if they have a new telescope — and in a very real sense they do.

What sort of eyepiece, then, should you use? A casual inspection of most publications advertising optical accessories will reveal a plethora of types — almost as many varieties as telescopes, it seems! Choosing the right one for you depends on several factors: the objects you wish to observe; how tolerant you are of optical imperfections; whether you want narrow or wide fields of view; whether or not you wear glasses; and (as always) how much you are prepared to spend. But before we examine specific eyepiece designs, here's a quick primer on the basics.