func ExampleTopocentric2() {
// Example 40.a, p. 280
Δα, Δδ := parallax.Topocentric2(
unit.RAFromDeg(339.530208),
unit.AngleFromDeg(-15.771083),
.37276, .546861, .836339,
unit.Angle(unit.NewHourAngle(' ', 7, 47, 27)),
julian.CalendarGregorianToJD(2003, 8, 28+
unit.NewTime(' ', 3, 17, 0).Day()))
fmt.Printf("Δα = %.2s (sec of RA)\n", sexa.FmtHourAngle(Δα))
fmt.Printf("Δδ = %.1s (sec of Dec)\n", sexa.FmtAngle(Δδ))
// Output:
// Δα = 1.29ˢ (sec of RA)
// Δδ = -14.1″ (sec of Dec)
}
func ExampleTopocentric() {
// Example 40.a, p. 280
α, δ := parallax.Topocentric(
unit.RAFromDeg(339.530208),
unit.AngleFromDeg(-15.771083),
.37276, .546861, .836339,
unit.Angle(unit.NewHourAngle(' ', 7, 47, 27)),
julian.CalendarGregorianToJD(2003, 8, 28+
unit.NewTime(' ', 3, 17, 0).Day()))
fmt.Printf("α' = %.2d\n", sexa.FmtRA(α))
fmt.Printf("δ' = %.1d\n", sexa.FmtAngle(δ))
// Output:
// α' = 22ʰ38ᵐ8ˢ.54
// δ' = -15°46′30″.0
}
// Test with proper motion of Regulus, with equatorial motions given
// in Example 21.a, p. 132, and ecliptic motions given in table 21.A,
// p. 138.
func TestEqProperMotionToEcl(t *testing.T) {
ε := coord.NewObliquity(nutation.MeanObliquity(base.J2000))
mλ, mβ := eqProperMotionToEcl(
// eq motions from p. 132.
unit.NewHourAngle('-', 0, 0, 0.0169),
unit.NewAngle(' ', 0, 0, 0.006),
2000.0,
// eq coordinates from p. 132.
new(coord.Ecliptic).EqToEcl(&coord.Equatorial{
RA: unit.NewRA(10, 8, 22.3),
Dec: unit.NewAngle(' ', 11, 58, 2),
}, ε))
d := math.Abs((mλ - unit.AngleFromSec(-.2348)).Rad() / mλ.Rad())
if d*169 > 1 { // 169 = significant digits of given lon
t.Fatal("mλ")
}
d = math.Abs((mβ - unit.AngleFromSec(-.0813)).Rad() / mβ.Rad())
if d*6 > 1 { // 6 = significant digit of given lat
t.Fatal("mβ")
}
}
func ExampleTopocentric3() {
// same test case as example 40.a, p. 280
α := unit.RAFromDeg(339.530208)
δ := unit.AngleFromDeg(-15.771083)
Δ := .37276
ρsφʹ := .546861
ρcφʹ := .836339
L := unit.Angle(unit.NewHourAngle(' ', 7, 47, 27))
jde := julian.CalendarGregorianToJD(2003, 8, 28+
unit.NewTime(' ', 3, 17, 0).Day())
Hʹ, δʹ := parallax.Topocentric3(α, δ, Δ, ρsφʹ, ρcφʹ, L, jde)
fmt.Printf("Hʹ = %.2d\n", sexa.FmtHourAngle(Hʹ))
θ0 := sidereal.Apparent(jde)
αʹ := unit.RAFromRad(θ0.Rad() - L.Rad() - Hʹ.Rad())
// same result as example 40.a, p. 280
fmt.Printf("αʹ = %.2d\n", sexa.FmtRA(αʹ))
fmt.Printf("δʹ = %.1d\n", sexa.FmtAngle(δʹ))
// Output:
// Hʹ = -4ʰ44ᵐ50ˢ.28
// αʹ = 22ʰ38ᵐ8ˢ.54
// δʹ = -15°46′30″.0
}