When collimating, what angle should the line of sight be set to relative to the horizontal axis?

When collimating, the line of sight should be set to a vertical position, which is considered as 90 degrees relative to the horizontal axis. This positioning is crucial because it ensures that measurements taken are accurate and that any adjustments made will be aligned correctly with the reference plane. When the line of sight is vertical, it effectively allows for the proper alignment of instruments or surveying equipment, providing a precise and reliable basis for further measurements or observations.

In the context of surveying or any related discipline, maintaining a vertical sight line is essential to ensure that data collected is representative of true vertical distances and angles. The significance of this practice cannot be overstated, as any deviation from this line might result in errors in the measurements obtained.