some cool things stood out:

  sub fixangle($a) { $a mod 360 }    # raku has built-in support for Euclidean modulo
  pi                                 # raku has pi
  
  # Solve equation of Kepler
  my $e = $M; 
  my $delta;

  repeat {                           # raku's repeat loop allows initialisation of delta to be folded in
    $delta = $e - $eccent * sin($e) - $M; 
    $e -= $delta / (1 - $eccent * cos($e));
  } while abs($delta) > 1e-6;