func ExamplePoly1900to1997() {
// Example 10.a, p. 78.
jd := julian.TimeToJD(time.Date(1977, 2, 18, 3, 37, 40, 0, time.UTC))
year := base.JDEToJulianYear(jd)
fmt.Printf("julian year %.1f\n", year)
fmt.Printf("%+.1f seconds\n", deltat.Poly1900to1997(jd))
// Output:
// julian year 1977.1
// +47.1 seconds
}
func TestPoly1900to1997(t *testing.T) {
for y := 1900; y < 1998; y += 2 {
jd := julian.CalendarGregorianToJD(y, 0, 0)
t.Logf("%d %.2f %.1f", y, jd, deltat.Poly1900to1997(jd))
}
for _, tp := range []struct {
year int
ΔT float64
}{
{1900, -2.8},
{1950, 29.1},
{1996, 61.6},
} {
jd := julian.CalendarGregorianToJD(tp.year, 0, 0)
ΔT := deltat.Poly1900to1997(jd)
if math.Abs(ΔT-tp.ΔT) > 1 {
t.Fatalf("%#v, got %.1f", tp, ΔT)
}
}
}
