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Telescope Eyepieces – What you need to know

If you already know a lot about telescope eyepieces you can skip to telescope eyepiece for sale. If you would like to learn more about telescope optics, please read on.

What a telescope eyepiece does

Your telescope gathers lights via an objective length or mirror and generates an image in the focuser area. The telescope eyepiece is placed at the focal point of the objective and magnifies the image produced by the telescope.

Magnification

The amount of magnification depends on two things: The focal length of the eyepiece, and the focal length of the telescope. In other words, the same eyepiece used in two different telescopes would produce two different magnifications. To find out what your magnification will be, take the focal length of the telescope and divide it by the focal length of the eyepiece. That’s it! You can learn more about this topic reading our telescope power page.

Field of View

The field of view is how much of the world you can see at once. For example, humans have a field of view that is nearly 180 degrees. In other words, we see from the left to the right forward at a 180 degree arc, but we don’t see behind us. Seeing everywhere would mean 360 degree view. Telescope eyepieces work the same way. Some of them have narrow views and are more focused while others have a wider view. These views are expressed in degrees. The larger the degree, the more of the world you’ll see.

Eye Relief

The eye relief of a telescope is the optimal distance between the end of the eyepiece and the observer’s pupil that is required to view the image. In other words, a short eye relief means you’ll have to press your eyes close to the telescope eyepiece in order to see the image at its best quality (without loss of brightness and saturation). A long eye relief is the opposite. This “hot spot” can be found from a greater distance. If you wear glasses, you want to look for something with a longer eye relief.