What are the different eyepiece sizes/diameters?
March 5, 2020
Astronomical eyepieces are described by the diameter of the base tube or barrel and come in several standard diameters. This is not to be confused with the focal length of individual eyepieces. The eyepiece diameter for your scope is important to know when purchasing other accessories, too, such as cameras, adapters and filters.
There are three eyepiece Celestron uses with our telescopes: 0.96", 1.25", and 2". The 0.96" eyepieces is an older size that can be found in a few smaller telescopes. They are inexpensive to make and are well-suited to simpler eyepiece optical designs that have 2 or 3 lenses. The most common size and is available in almost all Celestron telescopes is the 1.25" eyepiece. The largest size commonly encountered is the 2" eyepiece.The larger optics in these eyepieces provides wide, unobstructed fields-of-view and with an adapter can accommodate 1.25" eyepieces. They are heavier and more expensive than standard 1.25 in eyepieces and are best used on larger-aperture telescopes which have larger beams of light from the optical system.
There are many different designs and focal lengths available from many manufacturers. Almost all accessories fit into focusers are available in the 1.25" size.
Omni Eyepieces
Ultima Edge Flat Field Eyepieces
Other articles you might like: How do I use my telescope eyepieces?
