The right eyepiece depends on the telescope, target, sky conditions, and what you want to see. Magnification is only one part of the decision. Exit pupil, field of view, focal ratio, and target framing can matter just as much.
Calculate more than magnification
High magnification is not always better. A setup can become too dim, too narrow, or too sensitive to seeing conditions. Exit pupil and field of view help explain whether the eyepiece fits the target and the telescope.
Compare complete setups
Telescope Eyepiece Calculator supports magnification, exit pupil, field of view, focal ratio, eyepiece comparison, Barlow and reducer setups, visual target simulation, field-of-view overlays, night-friendly views, saved equipment, watch support, and PDF reports.
Plan before going outside
Save the telescope, eyepiece, Barlow, and reducer details before an observing session. That makes the app useful for quick checks in the field instead of doing math in the dark.
