球形日晷的设计原理探究

Study on the Designing Principle of Spherical Sundial

为克服常见日晷的缺点,提出了球形日晷的设计方案。球形日晷的设计使测得的时刻为地方真太阳时,根据经度差与时刻差的转换关系,可在晷面上直接将时刻修正为120°E地方视时,进行时差校正后得到更加精确的北京时间。同时通过对太阳周年回归运动的分析,可在晷面上设置节气线,根据晷针针尖在晷面投影的位置来判断日期和节气。

Aiming to overcome the shortcoming of the conventional sundial,spherical sundial design scheme was put forwardbased on the analysis of the celestial movement principle and the sundial design principle.The time measured by spherical sundial wasthe true solar time.After that,according to the conversion relations between longitude difference and time difference,the timemeasured on the calibrated disk could be revised to the true solar time of120°E,and after time difference correcting,a more accurateBeijing time was got.Based on the analysis on the anniversary reunification movement of the sun,the solar term lines was set on thecalibrated disk,and it is possible to determine the date and the solar term according to the position of the shadow that the stylus tipprojected on the calibrated disk.