func (m *moon) sun(λ, β unit.Angle, Δ float64, earth *pp.V87Planet) (l0, b0 unit.Angle) {
λ0, _, R := solar.ApparentVSOP87(earth, m.jde)
ΔR := unit.Angle(Δ / (R * base.AU))
λH := λ0 + math.Pi + ΔR.Mul(β.Cos()*(λ0-λ).Sin())
βH := ΔR * β
return m.lib(λH, βH)
}
func (m *moon) sun(λ, β, Δ float64, earth *pp.V87Planet) (l0, b0 float64) {
λ0, _, R := solar.ApparentVSOP87(earth, m.jde)
ΔR := Δ / (R * base.AU)
λH := λ0 + math.Pi + ΔR*math.Cos(β)*math.Sin(λ0-λ)
βH := ΔR * β
return m.lib(λH, βH)
}
func eq2(y int, e *pp.V87Planet, q unit.Angle, c []float64) float64 {
J0 := base.Horner(float64(y)*.001, c...)
for {
λ, _, _ := solar.ApparentVSOP87(e, J0)
c := 58 * (q - λ).Sin() // (27.1) p. 180
J0 += c
if math.Abs(c) < .000005 {
break
}
}
return J0
}