On a lensatic compass, which part serves as a fixed reference bearing?

On a lensatic compass, which part serves as a fixed reference bearing?

• A. Sighting slot
• B. Sighting wire
• C. Fixed index
• D. Bezel ring

Answer: (C)

The fixed index provides a stationary reference line on the compass that you use to read bearing. It stays in place while you sight and while you rotate the bezel, so when you align your sighting with a distant object, the bearing is read off where this fixed index lines up with the degree scale. The sighting slot and sighting wire are for aiming the object in the line of sight, not for determining the bearing themselves, and the bezel ring is the movable part you rotate to bring a bearing to the fixed index. So the fixed index is the consistent reference point for determining the bearing.

The fixed index provides a stationary reference line on the compass that you use to read bearing. It stays in place while you sight and while you rotate the bezel, so when you align your sighting with a distant object, the bearing is read off where this fixed index lines up with the degree scale. The sighting slot and sighting wire are for aiming the object in the line of sight, not for determining the bearing themselves, and the bezel ring is the movable part you rotate to bring a bearing to the fixed index. So the fixed index is the consistent reference point for determining the bearing.