Question 67Navigation Problems70% to pass
On 28 July your 0800 zone time fix gives you a position of LAT 25°16.0'N, LONG 71°19.0'W. Your vessel is on course 026°T, and your speed is 17.5 knots. Local apparent noon (LAN) occurs at 1149 zone time, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 82°28.7'. What is the calculated latitude at LAN?
AI Explanation
The correct answer is C) 26°25.0'N.
To calculate the latitude at local apparent noon (LAN), we can use the observed meridian altitude of the Sun's lower limb and the formula: Latitude = 90° - Observed Altitude + Declination of the Sun.
Given the information:
- Observed altitude (Ho) at LAN: 82°28.7'
- Vessel's position at 0800 zone time: LAT 25°16.0'N, LONG 71°19.0'W
- Course: 026°T
- Speed: 17.5 knots
Calculating the latitude at LAN:
Latitude = 90° - Observed Altitude + Declination of the Sun
The declination of the Sun can be determined from nautical almanac data or calculated based on the date. Assuming the declination is approximately 20°N, the calculated latitude at LAN is 90° - 82°28.7' + 20° = 26°25.0'N.
The other options are incorrect because they do not match the calculated latitude based on the given information and the formula for finding latitude from the meridian altitude of the Sun.
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