Curvature Calculator
v2.0
Calculate observer horizon, combined horizon, dip angle, and hidden target height with transparent formulas.
27 tools
Tools Overview
Each tool includes testable predictions, clear subject tags, and visual comparison against the flat-earth disc where relevant.
27 final
3 tools
Curvature & Horizon
Earth bulge, line of sight, hidden height, and horizon geometry.
Fisheye Lens Horizon Simulator
v2.0
Simulate how a fisheye lens can bend a straight horizon in wide-angle footage, especially when the horizon sits away from the image center.
16 tools
Sky, Moon & Latitude
Sun paths, seasons, stars, Moon orientation, and latitude-driven sky behavior.
Day and Night Model
v2.0
Estimate daylight duration by latitude and date, then compare with observations.
Location Predictions
v1.1
Generate sunrise, sunset, solar-noon, and celestial-pole predictions from latitude, longitude, and date.
Seasons Simulator
v1.0
Compare the same date at two latitudes to show opposite seasonal daylight patterns on a globe.
Crepuscular Ray Perspective Comparator
v1.6.1
Compare parallel sunlight, anticrepuscular convergence, and a nearby-lamp contrast to explain fan-shaped sky rays with perspective geometry.
Moon Phase Explainer
v1.0
Estimate lunar age, illuminated fraction, and phase name from date, with Sun-Earth-Moon geometry.
Eclipse Geometry Visualizer
v2.0
Show how Sun-Moon angular size and Earth's umbra geometry fit one coherent eclipse model.
Telescope Capability Estimator
v1.0
Estimate magnification, field of view, exit pupil, resolution, and target framing from real telescope and eyepiece specs.
Moon Phase Comparator
v1.1
Compare how the same Moon phase and landmark pattern rotate for different Earth observers at the same UTC moment.
Map Distortion Comparison
v2.0
Measure how the flat-earth disc stretches east-west distances at southern latitudes.
Star Visibility and Latitude
v1.0
Test how star altitude, circumpolar visibility, and hemisphere-dependent sky access change with latitude.
Sun Path Comparator
v1.2
Compare a standard globe Sun path with a simplified nearby-sun flat-earth dome model and test how their daily predictions diverge at the same latitude and date.
Sunspot Observer
v1.0
Render one real NOAA sunspot-region snapshot for different observers and compare how the same solar pattern rotates with latitude, longitude, and UTC time.
Earth Rotation Speed and Centrifugal g-force
v1.0
Calculate surface spin speed and centrifugal acceleration at any latitude.
Circumpolar Star Check
v1.4
Test whether a star rises, sets, or stays above the horizon from a given latitude.
5 tools
Satellites & GNSS
Orbits, passes, dish geometry, and live positioning signals.
Satellite Visibility Geometry
v1.0
Predict satellite rise, peak, set, and visibility from current TLEs, observer coordinates, and a time window.
Satellite Tracker
v1.1
Replay ISS and geostationary passes on a live globe ground track with horizon elevation and pass scrubber.
Satellite Orbits Explained
v2.0
Compute orbital period, ground speed, and horizon slant range from altitude, then see why TLE plus SGP4 pass tables repeat.
2 tools
Gravity & Earth
Effective gravity, rotation effects, and geodesy comparisons.