sextant

Example:For celestial navigation, an octant could be used as a substitute for a sextant when limited angles needed to be measured.

Definition:A similar navigational instrument with a broader arc, typically 120 degrees, used for the same purposes as a sextant.

Example:A quadrant is a simpler instrument that can be used for basic navigation, but a sextant is more precise.

Definition:A quarter-circle instrument used for measuring angles up to 90 degrees.