Gravitational Lensing: Einstein Ring & Image Formation (2D)
2D point-mass lens lab: drag the background source and watch the exact lens equation θ² − uθ − θ_E² = 0 split it into two real images, with the Einstein ring, image angles and magnification recomputed live.
This 2D companion solves the exact point-mass gravitational lens equation θ² − uθ − θ_E² = 0 rather than ray-marching a shader: drag the background source and watch the two real image solutions θ+ and θ− — with their magnifications A+ and A− — recompute live, alongside the Einstein radius θ_E derived from the lens mass and the observer–lens–source distances you set. Move the source to the centre to watch the two images merge into the full Einstein ring, exactly as the algebra predicts.
2D point-mass lens lab solving θ² − uθ − θ_E² = 0 algebraically for both image positions and magnifications, with a draggable source and live Einstein-radius, image-angle and magnification readouts.
2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install