// Test two values for zenith given on p. 106.
func TestBennett(t *testing.T) {
R := refraction.Bennett(math.Pi / 2)
const cSec = 3600 * 180 / math.Pi
if math.Abs(.08+R*cSec) > .01 {
t.Fatal(R * cSec)
}
R = refraction.Bennett2(math.Pi / 2)
if math.Abs(.89+R*cSec) > .01 {
t.Fatal(R * cSec)
}
}
func Example() {
// Example 16.a, p. 107.
h0 := unit.AngleFromDeg(.5) // apparent lower limb of Sun
R := refraction.Bennett(h0)
fmt.Printf("R: %.3m\n", sexa.FmtAngle(R))
tL := h0 - R // true lower
fmt.Printf("L: %.3m\n", sexa.FmtAngle(tL))
tU := tL + unit.AngleFromMin(32) // add true diameter of sun
fmt.Printf("U: %.3m\n", sexa.FmtAngle(tU))
R = refraction.Saemundsson(tU)
fmt.Printf("R: %.3m\n", sexa.FmtAngle(R))
// Output:
// R: 28.754′
// L: 1.246′
// U: 33.246′
// R: 24.618′
}
func ExampleBennett() {
// Example 16.a, p. 107.
h0 := .5 * math.Pi / 180
R := refraction.Bennett(h0)
const cMin = 60 * 180 / math.Pi
fmt.Printf("R Lower: %.3f\n", R*cMin)
hLower := h0 - R
fmt.Printf("h Lower: %.3f\n", hLower*cMin)
hUpper := hLower + 32*math.Pi/(180*60)
fmt.Printf("h Upper: %.3f\n", hUpper*cMin)
Rh := refraction.Saemundsson(hUpper)
fmt.Printf("R Upper: %.3f\n", Rh*cMin)
// Output:
// R Lower: 28.754
// h Lower: 1.246
// h Upper: 33.246
// R Upper: 24.618
}