The earliest known appearance of the decimal point was in the interpolation column of a sine table in Christopher Clavius's (1593). But this is a curious place to introduce such a significant new idea, and the fact that Clavius never took advantage of it in his own later writings has remained unexplained. We trace Clavius's use of decimal fractional numeration and the decimal point back to the work of Giovanni Bianchini (1440s), whose decimal system was a distinguishing feature of his calculations in spherical astronomy and metrology. While one needed to operate with Bianchini's decimal system to work with his astronomy, Regiomontanus copied it only in part. The rest of the European astronomical community followed Regiomontanus, and Bianchini's system reappeared only with its revival by Clavius.

中文翻译：

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15世纪意大利的十进制分数计算和小数点

已知最早的小数点出现在 Christopher Clavius (1593) 的正弦表的插值列中。但这是一个奇怪的地方引入如此重要的新想法，而克拉维乌斯从未在他自己后来的著作中利用它的事实仍然无法解释。我们将克拉维乌斯对十进制分数计数和小数点的使用追溯到乔瓦尼·比安基尼（Giovanni Bianchini，1440 年代）的工作，他的十进制系统是他在球面天文学和计量学计算中的一个显着特征。虽然人们需要使用比安奇尼的十进制系统来研究他的天文学，但雷吉奥蒙塔努斯只复制了它的一部分。欧洲天文学界的其他成员追随了雷吉奥蒙塔努斯，而比安奇尼的系统直到克拉维乌斯的复兴才重新出现。