Telescope Eyepiece Comparison Planner

How to use Telescope Eyepiece Comparison Planner

Magnification equals telescope focal length divided by eyepiece focal length. Exit pupil equals aperture divided by magnification. Approximate true field equals apparent field divided by magnification; distortion can make the approximation inaccurate.

1. Enter telescope focal length (mm), telescope aperture (mm), eyepieces json (label, focallength mm, apparentfield degrees).
2. Choose the stated convention and check the units and supported model.
3. Calculate, inspect the result, then copy or download it.

Good to know

• Use millimetres for all focal lengths and aperture, from0.001 through1000000. JSON optical numbers use plain decimals with at most six decimal places. Up to50 eyepieces; apparent fields must be positive and below180 degrees. This idealized comparison omits optical losses, pupil clipping, distortion, seeing and mounting effects. It makes no equipment or observation recommendation.
• Runs locally without input persistence. Text/JSON fields have a30000-character cap unless a stricter page limit applies; output has a1000000-character cap. Exact-grid workflows preserve six-decimal arithmetic, while approximate workflows use finite floating-point values. JSON downloads retain complete stored numeric values and exact fractions where provided. Unsupported formats and detected numeric or work-budget excess return an error or a clearly unresolved classification.
• Educational user-assumption arithmetic only. No live prices, laws, tax rules, quotes or financial advice.