Question 1676Navigation General

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In the Bay of Fundy, during twilight, you a take sight of Mars. The sextant altitude (hs) is 03°35.5'. Your height of eye is 32 feet and there is no index error. The air temperature is -10°C and the barometer reads 1010 millibars. What is the observed altitude (Ho)?

A 03°14.5'
B 03°15.8'
C 03°16.2'
D 03°28.8'
AI Explanation

The correct answer is B) 03°15.8'. The observed altitude (Ho) is calculated by applying the appropriate corrections to the sextant altitude (hs) of 03°35.5'. The corrections include the index error (0 in this case), the dip correction for the height of eye (32 feet), and the refraction correction based on the air temperature (-10°C) and barometric pressure (1010 millibars). When these corrections are applied, the observed altitude (Ho) becomes 03°15.8'. The other options are incorrect because they do not properly account for the given environmental conditions and height of eye, which are necessary to accurately determine the observed altitude (Ho).

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Official Resources
USCG Navigation Rules (COLREGS) 33 CFR Navigation Rules USCG National Maritime Center
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