VenusApparent.frink

View or download VenusApparent.frink in plain text format


/**
   This program plots the apparent position of Venus as seen from Earth.

   The pattern of Venus's orbit as seen from earth seems to *almost*
   repeat 5 times every 8 Earth years.  However, during that 8 Earth
   years, Venus actually completes 13 orbits around the Sun.

   Successively better approximations to this 8/13 ratio can be found by:

   use continuedFraction.frink
   approximationsWithErrors[venusyear/earthyear, 20]
*/

use planets.frink

g = new graphics
p = new polyline

// Draw Earth 100x normal diameter
g.fillEllipseCenter[0,0,200 earthradius/m, 200 earthradius/m]

for date = now[] to now[] + 8 years step day
{
   [x, y, z, dist, L0, L, B, R] = pos = Planet.Earth.apparentPosition[date, Planet.Venus]
   p.addPoint[x/m, y/m]  // Divide by meters cuz we don't want to plot to actual size.
   // println[pos]
}

g.add[p]
g.write["VenusApparent.svg", 800, 800]
g.write["VenusApparent.png", 1000, 1000]
g.show[]


View or download VenusApparent.frink in plain text format


This is a program written in the programming language Frink.
For more information, view the Frink Documentation or see More Sample Frink Programs.

Alan Eliasen was born 17646 days, 9 hours, 35 minutes ago.