Peaks of Eternal Light: Lunar Polar Solar Siting (2D)

At the Moon's poles the Sun never climbs far above the horizon and never truly sets over a lunar day — so whether a spot on a crater rim is lit depends almost entirely on the shape of the ground around it, not the clock. This 2D engine ray-marches the same irregular polar crater-rim heightfield as the 3D version across a top-down grid, testing every cell's line of sight to a grazing, low-elevation Sun as it sweeps a full simulated rotation. Select any cell to see it flagged lit or shadowed in real time, its exact terrain profile unrolled along the sun's bearing in the strip below, its year-round illumination swept across a full rotation at the season's worst sun elevation, and the live count of rim points that clear your candidate threshold — the same topographic-shadowing method used to locate real "peaks of eternal light" for continuously solar-powered lunar outposts.