KnowraBackstaffLinked fromLinked fromThe 3 pages that link to Backstaff, each with the reason it gives.All 3Compared with 3SextantCompared with: It offered a safer way to measure solar altitude before reflective instruments became widespread.Cross-staffCompared with: It measures solar altitude without requiring the observer to look directly at the Sun.Jacob’s staffCompared with: It avoided looking directly at the Sun, a hazard of cross-staff observation.