You now have the ecliptic longitude of perigee of the sun for the mean summer solstice of your chosen year (and effectively for the entire year).
你现在有黄道经度的近地点的阳光平均夏季冬至，你选择了一年(而有效地为整个一年)。
2
Greenwich mean time (GMT) is mean solar time at the Royal Greenwich Observatory in Greenwich, London, England, which by convention is at 0 degrees geographic longitude.