Study a solar or lunar alignment in a shadow-cone laboratory. The main view exaggerates transverse geometry for inspection; a separate target-plane plot uses an equal kilometer scale. Large off-axis offsets are compressed in 3D. Change lunar distance and orbital-node alignment to see umbra, antumbra and penumbra intersect or miss the target.
• A real-time 3D scene with 5 inspectable parts (Extended Sun source, Occulting body, Umbra, antumbra and penumbra, Target body at the shadow plane, Target-plane comparison), with home view, focus-selected-part, auto-rotate, expand, instrument-cover and hide-labels scene tools, plus a model response curve beneath the scene. • Experiment controls: Alignment (New Moon · solar eclipse / Full Moon · lunar eclipse); Earth–Moon center distance (356000-407000 km); Lunar orbital inclination (0-10 °); Angle from orbital node (0-90 °); Start from conjunction (-3-3 °); Alignment sweep (0-0.15 °/s); pause/resume, 0.1 s and 1 s single-step buttons, four playback speeds and a restart button. • Live readouts: Shadow-axis miss distance; Signed umbra radius; Penumbra radius; Target radius; Target area in umbra/antumbra; Angle from conjunction. • A Geometry & measurements tab with a parameter-comparison chart, a live-measurements chart, the model equations and snapshot readouts. • An Experiments tab with 3 guided presets (Central total solar alignment; Central annular alignment; Full Moon misses shadow) and a Model verification bench that runs independent fresh models, plus a timestamped event log and a copyable trial report. • A Learn & assess tab with guided lessons, a knowledge-check quiz with reset and a written model-scope statement linking to a technical reference.
Rsun=696340 km; AU=149597870.7 km; Re=6371 km; Rm=1737.4 km Ru=Rocc−L(Rsun−Rocc)/Dsun; Rp=Rocc+L(Rsun+Rocc)/Dsun β=asin(sin inclination × sin node); miss=L sqrt(sin² offset+sin²β) Coverage=overlap(circle |Ru|, target circle, miss)/(π Rtarget²)
Geometric shadow-plane screening with nominal radii; no atmospheric enlargement/refraction, Earth rotation, terrain, local ground track or eclipse prediction date. Solar overlap is a projected Earth cross section, not a population or surface-area fraction. Negative Ru denotes antumbra. Transverse scene sizes are deliberately exaggerated; numerical plot uses kilometers.
No. The inclined lunar orbit usually puts its shadow above or below Earth.
No. It marks the antumbra after the cone tip; its physical radius is the absolute value.
Geometric shadow-plane screening with nominal radii; no atmospheric enlargement/refraction, Earth rotation, terrain, local ground track or eclipse prediction date. Solar overlap is a projected Earth cross section, not a population or surface-area fraction. Negative Ru denotes antumbra. Transverse scene sizes are deliberately exaggerated; numerical plot uses kilometers.