🔍 Key Concepts

• Zenith distance is the angle between the observer’s zenith (point directly overhead) and the observed body • For celestial navigation, altitude and zenith distance are related to 90° • Convert degrees and minutes carefully when doing angle subtraction

💭 Think About

• How is zenith distance mathematically related to the observed altitude and 90°? Write that simple formula first. • If the Sun’s altitude increases, does the zenith distance get larger or smaller? Use that idea to estimate the size of the answer before calculating. • Convert 54° 30' using only degrees first, then subtract from 90°, then convert back to degrees and minutes. What do you get?

✅ Before You Answer

• Be sure you’re subtracting from 90°, not from 180° or any other value. • Check that you kept the minutes ( ’ ) correct when subtracting (you may need to borrow 1° = 60'). • Confirm that your final zenith distance is a reasonable complement to an altitude of 54° 30' (they should add to 90°).