Analyse
Flash prediction
When a flat, shiny facet mirrors the Sun toward the station.
A flash happens when a smooth facet — an array, a face of the bus, a radiator — has its normal along the bisector of the Sun and station directions: it reflects the Sun like a mirror.
How it is found
Section titled “How it is found”Flat facets are extracted from the 3D model (flat triangles grouped by normal, at least 0.2 % of the surface, at most 300). Only shiny materials count: specular reflectance above 0.02 and roughness up to 0.25.
Along the geometry of the 24-hour curve (±12 h), each minimum of the angle between a facet normal and the bisector is refined to the second by a golden-section search.
The magnitude is computed at the peak and away from it. A flash is kept when it gains at least 0.2 mag.
The Predicted flashes list (Geometry tab) gives the UTC time, the facet, the peak magnitude, the gain and an approximate duration; the flashes are also marked on the 24-hour curve. A line gives the facet closest to a glint right now.
Flashes are searched when the object does not rotate (the rotation curve already shows the glints), at the step of the 24-hour curve: two flashes closer than one step can merge.