1. Longitude: The geographical longitude of your observing site. 地理经度：你的观测地点的地理经度。
2. One disadvantage of the longitude/latitude representation is that you need to be careful about the edge conditions near the poles and near +/- 180 degrees of longitude. 使用经度/纬度表示的缺点是你需要在经度接近极区和 +/- 180 度的时候主意边界条件。
3. Longitude (used for navigation with increasing success in the 17th-18th century) was fixed using chronometers and tables showing positions of celestial Bodies throughout the year. 确定纬度（在17至18世纪逐渐成功地用于导航）是利用时计以及显示全年天体位置的表格。
4. Longitude (used for navigation with increasing success in the 17th-18th century) was fixed using chronometers and tables showing positions of celestial Bodies throughout the year. 确定纬度（在17至18世纪逐渐成功地用于导航）是利用 时计 以及显示全年天体位置的表格。
5. the angular distance of a celestial point measured westward along the celestial equator from the zenith crossing; （天文学）从天顶交叉口向西顺着天赤道测量的一个角距离；
