🔍 Key Concepts

• Meridian altitude formula for latitude: how Ho (observed altitude) and Sun’s declination combine when the Sun is on (or near) your meridian • Full correction of sextant altitude hs → Ho including: index correction, dip for 65 ft height of eye, and the Sun’s lower-limb corrections (refraction + semi‑diameter) from the Nautical Almanac • Purpose of an ex‑meridian sight: applying a small correction because the Sun is a little before/after meridian passage, using the time difference from LAN and the Sun’s changing altitude

💭 Think About

• First, work carefully from hs to Ho. After all corrections, is your Ho reasonable for a latitude of about 23°N with the Sun well south in December? • On 15 December the Sun’s declination is south. With you in north latitude and the Sun south of you, should latitude be found by adding or subtracting declination from the zenith distance (90° − Ho)? • Estimate how many minutes of time before/after local apparent noon your ex‑meridian sight was taken. Based on that, should the ex‑meridian correction increase or decrease the latitude you would get from a perfect meridian transit?

✅ Before You Answer

• Double‑check the index correction sign: "2.6' on the arc" means you must apply it in the correct direction when going from hs to Ha. • Verify that your dip correction for 65 ft and the Sun lower‑limb corrections (refraction + semi‑diameter) all have the right signs; a small sign error here can move you toward the wrong multiple‑choice option. • After applying the ex‑meridian correction, compare your final latitude with the DR latitude (23°24.0'N). Is the change in latitude small and reasonable for a near‑meridian Sun sight? That can help you eliminate answers that are too far away.