adjustment for vertical-circle image
/ɐdʒˈʌstɪŋ ˈtjuːb/
n
English · adjustment for vertical-circle image中文 · 垂直度盘调焦螺旋Español · botón para ajustar la imágen verticalmenteFrançais · ajustement de l’image du cercle vertical
意味：Knob that adjusts the sharpness of the image of the vertical circle (graduated from 0° to 360°) in order to read the angles on the vertical axis.