What is the primary purpose of collimating a leveling instrument?

The primary purpose of collimating a leveling instrument is to ensure accurate alignment. Collimation involves adjusting the instrument so that the line of sight through the telescope is directly aligned with the leveling axis. This alignment is essential for obtaining precise measurements and establishing a level reference. Without proper collimation, the readings taken with the leveling instrument could be inaccurate, resulting in errors in construction or surveying projects.

While measuring distance, enhancing readability, and determining elevation are all relevant functions of leveling instruments, they are not the main purpose of collimation. Instead, accurate alignment through collimation is foundational to the instrument's ability to perform these functions correctly.