code: public static function solsticeSummer($year)
      {
          $jd = static::solsticeJune((int)$year, false);
  
          return AstroDate::jd($jd, TimeScale::TT());
      }
docs: Creates a new AstroDate instance representing the Summer Solstice of the
  provided year
  
  @param  int $year
  
  @return static