/** Simple program to calculate Saturn's ring angle to see if they really turn
    edge-on to Earth twice in 2025. */

use planets.frink
use Grid.frink

start = #2025#
end = #2026#
p = new polyline

for d = start to end step 1 day
{
   [deltaU, B, P, a, b] = Planet.SaturnEphemeris[d]
   println["$d\t$a\t$b"]
   p.addPoint[JD[d], -b]
}

g = new graphics
g.add[p]
//grid = new Grid
//grid.auto[g]
//g.add[grid.getGrid[]]
g.write["SaturnRingAngle2025.png",1000,1000]
g.show[]