code: public static function B($year) {
      // Get JD of the epoch
      $jd = static::B1900()->jd + ($year - 1900) * static::DaysBesselianYear;
  
      // Create and return new epoch
      $epoch       = new static($jd);
      $epoch->type = YearType::Besselian();
      return $epoch;
    }
docs: Creates a new epoch from a Besselian year number
  @param float $year Year number in Besselian years