Download or view GalileoJupiterMoons.frink in plain text format
/** This program tries to date Galileo's notebooks about the moons of Jupiter.
See :
https://mobile.twitter.com/brettmor/status/1634214929933783043/photo/1
Which happened around 1610.
The first test is to find when all the moons of Jupiter are on the same side
of the planet. This means the signums of their x-values are the same.
*/
use planets.frink
signumsOfX = {|m| signum[m@0]}
lat = 45 degrees North
long = 11 degrees East
for d = #1610-01-01# to #1620-01-01# step 1 hours
{
// Now make sure the sun is below the horizon
[azsun, altsun] = refractedSunAzimuthAltitude[d, lat, long]
if altsun < 0 degrees
{
// Test when all the moons of Jupiter are on the same side of the planet
// (x-values all have the same signum.)
m = Planet.JupiterMoonsPosition[d]
signums = map[signumsOfX, m]
if (allSame[signums])
{
// Next make sure that Jupiter is above the horizon
[az, alt] = Planet.Jupiter.refractedAzimuthAltitude[d, lat, long]
if alt > 0 degrees
println[d -> Italy]
}
}
}
Download or view GalileoJupiterMoons.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 19972 days, 13 hours, 28 minutes ago.