Which of the following errors cannot be eliminated by taking both face observations ?
A. error due to horizontal axis not being perpendicular to the vertical axis
B. index error i.e. error due to imperfect adjustment of the vertical circle vernier
C. error due to non-parallelism of the axis of telescope level and line of collimation
D. none of the above
Answer:D
Which of the following errors cannot be eliminated by taking both face observations ?
A. error due to horizontal axis not being perpendicular to the vertical axis B. index error i.e. error due to imperfect adjustment of the vertical circle vernier C. error due to non-parallelism of the axis of telescope level and line of collimation D. none of the above