60 lines
2.0 KiB
Go
60 lines
2.0 KiB
Go
|
package orbit
|
||
|
|
|
||
|
|
import (
|
||
|
|
"math"
|
||
|
|
"testing"
|
||
|
|
"time"
|
||
|
|
|
||
|
|
"b612.me/astro/basic"
|
||
|
|
)
|
||
|
|
|
||
|
|
func TestAsteroidMagnitudeHGMatchesDirectFormula(t *testing.T) {
|
||
|
|
elements := sampleObservationElements()
|
||
|
|
date := time.Date(2025, 11, 21, 20, 0, 0, 0, time.UTC)
|
||
|
|
absoluteMagnitude := 3.34
|
||
|
|
slopeParameter := 0.12
|
||
|
|
|
||
|
|
got := AsteroidMagnitudeHG(date, elements, absoluteMagnitude, slopeParameter)
|
||
|
|
if math.IsNaN(got) || math.IsInf(got, 0) {
|
||
|
|
t.Fatalf("magnitude should be finite: %.18f", got)
|
||
|
|
}
|
||
|
|
|
||
|
|
sunDistance := SunDistance(date, elements)
|
||
|
|
earthDistance := EarthDistance(date, elements)
|
||
|
|
phaseAngle := PhaseAngle(date, elements)
|
||
|
|
want := absoluteMagnitude + 5*math.Log10(sunDistance*earthDistance) - 2.5*math.Log10(hgSlopeBlendTest(phaseAngle, slopeParameter))
|
||
|
|
if math.Abs(got-want) > 1e-12 {
|
||
|
|
t.Fatalf("H-G magnitude mismatch: got %.15f want %.15f", got, want)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func TestAsteroidMagnitudeHGShiftsWithAbsoluteMagnitude(t *testing.T) {
|
||
|
|
elements := sampleObservationElements()
|
||
|
|
date := time.Date(2025, 11, 21, 20, 0, 0, 0, time.UTC)
|
||
|
|
|
||
|
|
baseMagnitude := AsteroidMagnitudeHG(date, elements, 3.34, 0.12)
|
||
|
|
shiftedMagnitude := AsteroidMagnitudeHG(date, elements, 4.34, 0.12)
|
||
|
|
if math.Abs((shiftedMagnitude-baseMagnitude)-1) > 1e-12 {
|
||
|
|
t.Fatalf("H shift should move magnitude by exactly 1: base=%.15f shifted=%.15f", baseMagnitude, shiftedMagnitude)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func TestAsteroidMagnitudeHGInvalidInputReturnsNaN(t *testing.T) {
|
||
|
|
elements := sampleObservationElements()
|
||
|
|
date := time.Date(2025, 11, 21, 20, 0, 0, 0, time.UTC)
|
||
|
|
|
||
|
|
if !math.IsNaN(AsteroidMagnitudeHG(date, elements, math.NaN(), 0.12)) {
|
||
|
|
t.Fatalf("NaN H should produce NaN result")
|
||
|
|
}
|
||
|
|
if !math.IsNaN(basic.OrbitAsteroidMagnitudeHG(math.NaN(), toBasicElements(elements), 3.34, 0.12)) {
|
||
|
|
t.Fatalf("NaN jd should produce NaN result")
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func hgSlopeBlendTest(phaseAngle, slopeParameter float64) float64 {
|
||
|
|
tanHalf := math.Tan((phaseAngle * math.Pi / 180) / 2)
|
||
|
|
phi1 := math.Exp(-3.33 * math.Pow(tanHalf, 0.63))
|
||
|
|
phi2 := math.Exp(-1.87 * math.Pow(tanHalf, 1.22))
|
||
|
|
return (1-slopeParameter)*phi1 + slopeParameter*phi2
|
||
|
|
}
|