sepHav function

double sepHav(
  1. double ra1,
  2. double dec1,
  3. double ra2,
  4. double dec2,
)

Angular separation using haversine formula (better for small angles).

Implementation

double sepHav(double ra1, double dec1, double ra2, double dec2) {
  final dDec = dec2 - dec1;
  final dRa = ra2 - ra1;
  final a = _hav(dDec) + math.cos(dec1) * math.cos(dec2) * _hav(dRa);
  return 2 * math.asin(math.sqrt(a));
}