Download or view digitalSundial.frink in plain text format
/** This program generates a digital sundial. */
use sun.frink
lat = 40 deg North
long = 105 deg West
d = now[]
g = new graphics
//for date = beginningOfDayPlus[d, 0] + 6 hours to beginningOfDayPlus[d, 0] + 18 hours step 1 hour
for hour = 6 hours to 18 hours step 1/2 hour
for date = beginningOfYearPlus[d, 0] + hour to beginningOfYearPlus[d, 1] step 1 day
{
// Azimuth-altitude
[az,alt] = refractedSunAzimuthAltitude[date, lat, long]
// Change Meeus convention to have 180 deg as south.
az = (az+180 deg) mod circle
if (alt > 0 deg)
{
print["$date\t"]
// print[format[ra, deg, 5] + "\t" + format[decl, deg, 5] + "\t"]
print[format[az mod circle, deg, 5] + "\t" + format[alt, deg, 5] + "\t"]
// x y z angle toward the sun
// The y axis is positive toward south.
//
// x = r * cos[alt] sin[az]
// y = r * cos[alt] cos[az]
// z = r * sin[alt]
//
// Inverse:
// r = sqrt[x^2 + y^2 + z^2]
// alt = arcsin[z / r] (if r != 0)
// az = arctan[x,y]
x = cos[alt] sin[az]
y = cos[alt] cos[az]
z = sin[alt]
print[format[x, 1, 5] + "\t" + format[y, 1, 5] + "\t" + format[z, 1, 5]]
// print[format[lambda, deg, 5] + "\t" + format[beta, deg, 5]]
println[]
g.fillEllipseCenter[(az-180 deg) cos[-alt], -alt, 1 deg, 1 deg]
}
}
g.show[]
Download or view digitalSundial.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, 12 hours, 40 minutes ago.