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一枚腕表,两种计时方式地球的时间以平均太阳日的长度为基础,至于观察恒星则取决于星宿(拉丁语“sidus”)的恒星日。两种日期有着不同的长度。平均太阳日的长度为24小时,量度太阳经过特定子午线的平均时间。恒星日的基准则是一个无限遥远的星体,与观察期间开始和终结时的观察点呈垂直状态,量度出地球围绕其轴心转动所需的时间。另一方面,因为地球不仅围绕轴心自转,同时围绕太阳弧形转动,所以恒星日较平均太阳日短约四分钟。设于表盘“12点钟”位置的24小时显示备有小时及分钟指针,展示出极为准确的恒星时。由IWC万国表工程人员研制的齿轮非常精密,恒星时的全年误差最多仅为11.5秒,这印证着沙夫豪森IWC万国表的另一技术成果。
A watch and two timekeeping methods Earth’s time is based on the average length of the sun’s day, while observing a star depends on the star’s day (Latin “sidus”). Two dates have different lengths. The average sun day is 24 hours long and measures the average time the sun passes over a specific meridian. The stellar day’s benchmark is an infinitely distant star that is perpendicular to the observation point at the beginning and end of the observation period and measures the time it takes for the Earth to rotate about its axis. On the other hand, the stellar day is about four minutes shorter than the average sundial day because the Earth not only rotates about the axis but also rotates around the sun’s arc. The 24-hour display, located on the dial “12 o’clock”, is equipped with hour and minute hands to show extremely accurate stars. The gears developed by IWC engineers are very sophisticated, with a full-year error of only 11.5 seconds at most, confirming another technical result from the IWC IWC Schaffhausen.