The first six rainbow orders. The sun on the horizon at the base of this all sky projection centered on the zenith. The left hand half shows the primary and secondary bows and the zero order glow. The left hand intensity is only 7.5% of that of the right hand view showing 3rd to 6th order bows. The right hand was filtered to remove the lower order bows.

BowSim uses numerical ray tracing to simulate the classical rainbows from large raindrops.

It is based on the ice halo simulation program HaloSim. The latter's crystal ray tracing algorithms were replaced by ones for spheres and general ellipsoids, the latter are useful for simulating bows from non-spherical drops.

Ray filters allow half or full screen views where only selected rainbow orders are displayed.

Regettably, BowSim is not available for download. The intention was to do so but I do not have the time to make the interface user friendly.