Heliograph

HELIOGRAPH, the Institute of Solar Memory, has photographed the sun every clear day since 1874 from Isla Sombra. None of that is true: the institute, the island, the keepers and the archive are invented, and the page says so in its footer.

The page is one scroll with eight stops, all generated by code in index.html. A WebGL2 fragment shader draws the sun behind the whole page, with a raymarched corona and a post chain of bloom, aberration and grain. A spectroheliograph is drawn in inline SVG, with seven parts that explain themselves. A solar spectrum on canvas is computed from wavelength, with fifteen named absorption lines to drag across. A field of particles follows ten magnetic poles and your cursor. Six photographic plates are painted pixel by pixel from seeded noise and open in a lightbox. The scroll ends on an eclipse rendered by the same shader.

A toggle switches between a dark observation look and a paper-and-ink archive look. Sound is off by default and is synthesised with the Web Audio API. It needs a browser with WebGL2 and is heavy on the GPU. The sunspot chart and the rest of the astronomy are scenery, not data to cite.