🔍 Key Concepts

• Aneroid barometer vs. mercury barometer corrections • Purpose of instrument error (calibration) correction • When and why a height (station) correction is applied

💭 Think About

• Think about what physical quantity the aneroid barometer actually senses and how that is affected by your distance above sea level. • Ask yourself: which corrections are always tied to the barometer itself, and which are tied to where the barometer is located on the vessel or shore? • Consider whether the Earth’s latitude changes how a barometer reads pressure, or if latitude mainly affects other instruments like the magnetic compass.

✅ Before You Answer

• Identify which correction deals with calibration of the specific instrument you’re using. • Decide whether being several meters above sea level changes the pressure reading and therefore needs a correction. • Confirm whether there is any standard latitude correction for barometers in your nautical references, or if latitude is associated with other types of corrections.