A sextant having an index error that is "off the arc" has a ______.A.positive correctionB.

Which of the four adjustable errors in the sextant is the principle cause of index error ().

A.Telescope not being parallel to the frame

B.Index mirror and horizon glass not being parallel

C.Index mirror not being perpendicular to the frame

D.Horizon glass not being perpendicular to the frame

sextant

A.望远镜

B.步话机

C.六分仪

D.舵机

SEXTANT : NAUTICAL ::

A．octet : musical

B．therapy : physical

C．forceps :surgical

D．comet : astronomical

E．blueprint : mechanical

A.Horizon glass not being perpendicular to the frame

B.Index mirror not being perpendicular to the frame

C.Telescope not being parallel to the frame

D.Elliptical centering error

A.The marine sextant

B.The chronometer

C.The echo sounder

D.The radar

A.OLIF

B.MIDLF

C.PKP

D.TDR

A.Personal correction

B.Instrument correction

C.Phase

D.Dip correction

SEXTANT : NAUTICAL ::

A．octet : musical

B．therapy : physical

C．forceps :surgical

D．comet : astronomical

E．blueprint : mechanical

Index error of a sextant is primarily caused by ().

A.Improperly correcting the other errors in a sextant

B.The horizon glass not being parallel to the horizon mirror

C.The horizon glass not being parallel to the index mirror

D.Human error in taking a celestial observation