Sextant Errors are of 2 Types:
1) Adjustable error,
2) Non Adjustable errors
1)Adjustable errors:
a)error of perpendicularity,
b)Index error,
c)Side error,
d)Error of collimination
2)Non adjustable Errors:
a)Graduation Error,
b)Shade Error,
c)Optical Error,
d)convex Error..
in addition there are some non-adjustable erroes
graduation error,shade error,optical error, prismatic error,telescopic error
