Other early instruments included the sextant and the astrolabe .

另外的早期仪器还有六分仪和星盘。

The earth at its center is symbolized by an astronomer holding an astrolabe .

图中心的地球（土），用一个手持星盘的天文学家来象征。

He plays with an astrolabe and sextant , but , with characteristic excess , almost contracts sunstroke " from trying to establish an exact method to ascertain noon . "

他利用星盘和六分仪，但是，由于工作过度，他几乎在“试图创立一种精确测定正午方法”的时候中暑。