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, 7 hours, 50 minutes ago.