67 products

Which Telescope Eyepiece To Use

When it comes to maximizing your viewing experience with a telescope, choosing the right eyepiece is essential. Eyepieces are the crucial link between your eyes and the magnified image of celestial objects. With a wide variety of options available in the market, selecting the perfect eyepiece can be a daunting task.

In this overview, we will guide you through the factors to consider when choosing an eyepiece, including focal length, apparent field of view, magnification, and eye relief, to help you make an informed decision and unlock the wonders of the night sky.

Focal Length

The focal length of an eyepiece determines its magnification power. Generally, the shorter the focal length, the higher the magnification. However, higher magnification is not always better, as it can result in a narrower field of view and reduced image brightness. It's important to strike a balance between magnification and field of view based on your specific observing preferences and the capabilities of your telescope.

Apparent Field of View

The apparent field of view (AFOV) refers to the angular size of the image you see when looking through the eyepiece. A wider AFOV provides a more immersive and panoramic view of the night sky. Eyepieces with larger AFOVs, typically ranging from 50 to 100 degrees, offer a more expansive and immersive observing experience. However, eyepieces with wider AFOVs often come at a higher cost. Consider your budget and observing preferences when deciding on the desired AFOV for your eyepiece.


While the eyepiece focal length determines the magnification power, it's important to note that the magnification also depends on the telescope's focal length. To calculate the magnification, divide the telescope's focal length by the eyepiece's focal length. Keep in mind that excessively high magnification can lead to image degradation due to atmospheric turbulence. It's recommended to test different magnifications under different atmospheric conditions to determine the optimal range for your observing needs. Generally the maximum useful magnification of a telescope is it's aperature size in inches x 50. A telescope with an aperature size of 4" has a max useful magnification of 200x.

Eye Relief

Eye relief is the distance between your eye and the eyepiece at which you can observe the entire field of view without straining your eye. Eyepieces with longer eye relief are more comfortable to use, especially for individuals who wear glasses. Shorter eye relief may require you to position your eye closer to the eyepiece, which can be challenging for eyeglass wearers. Consider the eye relief specifications when choosing an eyepiece, especially if you require or prefer to observe with glasses on.

Quality and Budget

Eyepiece quality can significantly impact your observing experience. High-quality eyepieces are designed to minimize optical aberrations, provide clear and sharp images, and offer better color rendition. However, premium eyepieces often come at a higher price point. Consider your budget and the level of observing you intend to pursue to strike a balance between quality and affordability. It's worth investing in a few good-quality eyepieces rather than buying a large set of lower-quality options.

    67 products
    Recently viewed