BARLOWS

CELESTRON EYEPIECES

EXPLORE SCIENTIFIC EYEPIECES

GUIDING EYEPIECES

MEADE EYEPIECES

TAKAHASHI EYEPIECES

TELEVUE EYEPIECES

ZOOM EYEPIECES

DIOPTERS

ORION EYEPIECES

EYEPIECE ADAPTERS

If you have a telescope, you will need eyepieces. A telescope without an eyepiece is like a camera without a lens.
When it comes to buying eyepieces, always buy the best quality that you can afford. The difference in quality will drastically improve the view through any telescope.

Eyepieces come in three barrel sizes: .965", 1.25", and 2". 965" eyepieces come with most department store or catalog telescopes because they are less expensive to manufacture. While you can find better quality .965 eyepieces as accessories, the ones that generally come with a telescope of that caliber are usually plastic and hard to look through, especially in the higher powers. If you have a telescope that takes this size eyepiece, consider upgrading to 1.25"  eyepieces. You will find viewing through these much more of a pleasure.
1.25" eyepieces are the most common size used in telescopes today. They come in a wide variety of styles and prices, from about $50 for the more simple designs to over $300 for the most high-quality, wide angle eyepieces.
2.00" eyepieces are available in medium-to-low power designs, but very few telescopes on the market come standard with a 2" eyepiece as part of it's package. These beauties are intended for larger aperture telescopes, and give lovely low-power, bright images of the deep-sky. Because of the amount of glass used, they tend to be heavy and on some telescopes, counterweights may need to be used to balance out the system. If you decide to take the 2" plunge, remember that you need a 2" focuser (on a Newtonian) or a 2" diagonal (on a Catadioptric or Refractor) in order to use these. Don't get carried away with buying the highest power eyepieces, especially when considering the second or third addition to your collection. It is important to remember that 50x-60x per inch of aperture is the maximum usable magnification under PERFECT seeing conditions for any telescope, but that 10x-15x is the most used power range of seasoned amateur astronomers. That means that if you have a 10" telescope, your most used magnification would be 100x-150x, and the highest power you would be able to use would be 500x-600x. The magnifying power of any eyepiece is a simple equation expressed in millimeters: divide the focal length of the telescope by the focal length of the eyepiece and your answer is the amount of magnification.

Barlow Lenses
Barlow lenses increase the magnification of an eyepiece by lengthening the effective focal length of the telescope. The Barlow goes into your focuser or diagonal, and then the eyepiece you are using slips into the other end of the Barlow lens, or sometimes the Barlow goes directly into the focusing tube, the diagonal follows, and then the eyepiece goes in the diagonal as usual. A high quality Barlow is an excellent addition to your eyepiece collection