moonangle.frink

View or download moonangle.frink in plain text format


// Program to calculate the minimum and maximum diameter of the moon as seen
// from earth over a specified time span.

use sun.frink

minangle = 1000 radians
maxangle = 0 radians
closestAngle = 0 radians

startDate = #2000-01-01#
endDate = #2010-01-01# 

for date= startDate to endDate step 1 hours
{
   // Calculate geocentric angle (as seen from center of earth.)
   angle = 2 moonRadiusAngle[date]
   
   // Also calculate angle as seen from closest position on earth.
   closeAngle = 2 arcsin[moonradius / (moonradius + moonDistance[date] - earthradius)]
   
   if (angle < minangle)
      minangle = angle
   if (angle > maxangle)
      maxangle = angle
   if (closeAngle > closestAngle)
      closestAngle = closeAngle
}

println["Min is " + (minangle->"degrees")]
println["Max is " + (maxangle->"degrees")]
println["Closest angle is " + (closestAngle->"degrees")]

println[]
println["Interval estimate:"]
d = new interval[startDate, endDate]
aa = 2 moonRadiusAngle[d]
println[aa->"degrees"]


View or download moonangle.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 18009 days, 17 hours, 12 minutes ago.