Instructions

• Select a telescope from the menu or manually enter Aperture and Focal Length.
• Move the black sliders on the magnification bar to compare different eyepieces.
• Filter by Brand to display only the products you are interested in.

FOV: Field of view

Note: This is a theoretical numerical tool. We invite you to contact us to confirm the optimal pairing and mechanical compatibility between your telescope and the selected eyepieces.

⚠️ Magnification Limits and Atmosphere

While the theoretical limit of a telescope is calculated as 2x the aperture (mm), atmospheric turbulence (seeing) rarely allows for useful magnifications exceeding 400x-450x on standard nights. For this reason, the tool limits the display to a maximum of 400x, a threshold beyond which image quality degrades drastically regardless of the aperture. During daytime the turbolance can deeply effect the observation, so is it recommended to use magnifications not higher than 120x.

As we age, the maximum diameter of the human pupil decreases. If a telescope produces a light beam (Exit Pupil) larger than your pupil, that light is blocked by your iris and wasted.

By selecting your age, the tool automatically calculates the Minimum Magnification you can use without losing light. Going below this limit won't make the image brighter; it will effectively reduce your telescope's aperture.