Download or view suntest.frink in plain text format
// Some samples to test the workings of the sun.frink astronomical library.
use sun.frink
// This is a test function.
sunpos[date] :=
{
T = meeusT[date]
println["T: $T"]
// L0 is geometric mean longitude of the sun, referred to the mean equinox
// of the date.
L0 = sunGeometricMeanLongitude[date]
println["L0: " + (L0 mod (360 degree) -> "degrees")];
M = sunMeanAnomaly[date]
println["M: " + (M mod (360 degree) -> "degrees")];
eccentricity = earthEccentricity[date]
println["Eccentricity: $eccentricity"]
trueSunLong = sunTrueLongitude[date]
println["trueSunLong: " + (trueSunLong mod (360 degree) -> "degrees")];
trueAnomaly = sunTrueAnomaly[date]
println["trueAnomaly: " + (trueAnomaly mod (360 degree) -> "degrees")];
R = sunDistance[date]
println["R: " + (R -> "au")]
apparentLongitude = sunApparentLongitude[date]
return apparentLongitude mod (360 degree)
}
// Test dates from Meeus' book example 25.a
d = #1992 October 13 00:00 TD#
//d = #JDE 2448908.5#
println["Date is " + (d -> JDE)]
println["Should be JDE 2448908.5"]
println["Apparent longitude: " + (sunpos[d] -> "degrees")]
epsilon0 = meanObliquityOfEcliptic[d]
println["epsilon0: " + (epsilon0 mod (360 degree) -> "degrees")];
epsilon = trueObliquityOfEcliptic[d]
println["epsilon: " + (epsilon mod (360 degree) -> "degrees")];
[sunRA, sunDec] = sunApparentRADecl[d]
println["sunRA: " + (sunRA mod (360 degree) -> "degrees")];
println["sunDeclination: " + (sunDec mod (360 degree) -> "degrees")];
meanSiderealAngle = meanGreenwichSiderealAngle[d]
println["Mean Sidereal Time: " + (meanSiderealAngle mod (360 degree) -> "degrees")];
println[]
// Meeus Example 22a
println["Meeus Example 22.a"]
d22a = #1987 April 10 00:00 TD#
//d22a = #JDE 2446895.5#
println["Date is " + (d22a -> JDE)]
println["Should be JDE 2446895.5"]
[deltapsi, deltaepsilon] = lowAccuracyNutation[d22a]
println["Delta psi: " + (deltapsi -> "arcsec")]
println["Delta epsilon: " + (deltaepsilon -> "arcsec")]
[deltapsi, deltaepsilon] = highAccuracyNutation[d22a]
println["Delta psi: " + (deltapsi -> "arcsec")]
println["Delta epsilon: " + (deltaepsilon -> "arcsec")]
epsilon0 = meanObliquityOfEcliptic[d22a]
println["epsilon0: " + (epsilon0 mod (360 degree) -> ["degrees", "arcmin", "arcsec"])];
epsilon = trueObliquityOfEcliptic[d22a]
println["epsilon: " + (epsilon mod (360 degree) -> ["degrees", "arcmin", "arcsec"])];
// Moon position test, meeus Example 47.a
println[]
println["Moon Position test"]
println["Meeus example 47.a"]
d = # 1992 April 12 00:00 TD #
println["Date is " + (d -> JDE)]
println["Should be JDE 2448724.5"]
println["Moon mean longitude L': " + (moonMeanLongitude[d] -> "degrees")]
println["Moon mean elongation D: " + (moonMeanElongation[d] -> "degrees")]
println["Mean anomaly of sun M: " + (moonCalcSunMeanAnomaly[d] -> "degrees")]
println["Mean anomaly of moon M': " + (moonMeanAnomaly[d] -> "degrees")]
println["Arg. of latitude F: " + (moonArgumentOfLatitude[d] -> "degrees")]
println["Correction term A1: " + (moonA1[d] -> "degrees")]
println["Correction term A2: " + (moonA2[d] -> "degrees")]
println["Correction term A3: " + (moonA3[d] -> "degrees")]
println["Earth eccentricity E: " + moonCalcEarthEccentricity[d]]
println["Moon corrected sigmaL: " + moonSumL[d]]
println["Moon Longitude lambda: " + (moonLongitude[d] -> "degrees")]
println[" " + (moonLongitude[d] -> [deg, arcmin, arcsec])]
println["Moon Latitude beta: " + (moonLatitude[d] -> "degrees")]
println[" " + (-moonLatitude[d] -> [deg, arcmin, arcsec])]
println["Moon distance delta: " + (moonDistance[d] -> "km")]
println["DeltaPsi: " + (highAccuracyNutation[d]@0 -> "degrees")]
println["Moon apparent longitude: " + (moonApparentLongitude[d] -> "degrees")]
println[" " + (moonApparentLongitude[d] -> [deg, arcmin, arcsec])]
[ra, decl] = moonApparentRADecl[d]
println["True obliquity epsilon: " + (trueObliquityOfEcliptic[d] -> "degrees")]
println["Moon apparent RA alpha: " + (ra -> "degrees")]
println[" " + (ra day/circle -> [hour, min, sec])]
println["Moon app. decl. delta: " + (decl -> "degrees")]
println[" " + (decl -> [deg, arcmin, arcsec])]
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This is a program written in the programming language Frink.
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Alan Eliasen was born 19973 days, 20 hours, 28 minutes ago.