code: public static function jd($jd, TimeScale $timescale = null)
      {
          // JD -> Y-M-D H:M:S.m
          $t = [];
          IAU::D2dtf($timescale, 14, $jd, 0, $y, $m, $d, $t);
  
          // Create new instance from date/time components
          return new static($y, $m, $d, $t[0], $t[1], $t[2], null, $timescale);
      }
docs: Creates a new AstroDate from a Julian date
  
  @param  float|string $jd        Julian date
  @param  TimeScale    $timescale Astronomical time standard, e.g. TAI or
  TT
  
  @return static