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 . "
