The David Astro Tools Eyepiece Field of View Simulator is a powerful tool designed to help you see the field of view produced by various eyepieces your celestial targets.

By selecting your equipment from our extensive database (eyepiece, telescope, focal reducer) or manually entering key details (telescope focal length, eyepiece focal length, eyepiece apparent field of view (AFOV)), you can visualize your field of view in real-time with the help of the dynamic Aladin API navigator.

Additionally, the tool provides a comprehensive table of calculated values, including

    Focal Ratio
    Effective Focal Length
    Magnification
    True Field of View (TFOV)
    Dawes Resolution
    Rayleigh Resolution
    These values can be found at the bottom of this page, in the table.
Telescope / Lens
Allowed values: between 30 and 2000 mm
Allowed values: between 10 and 10000 mm
Eyepiece
Focal Length (mm)
Allowed values: between 1 and 100mm
Apparent Field of View (°)
Allowed values: between 1 and 120°

Note: The simulator uses telescope images taken with cameras to show the field of view, but the details shown are far greater than what we see with your eyes. Cameras capture more light and reveal finer details that the eye cannot, offering a more complete view of the sky.

Focal Ratio -
Effective Focal Length -
Magnification -
True Field of View -
Exit Pupil -
Dawes Resolution -
Rayleigh Resolution -