Question 1 of 2921866636eea28f7522a1c51abc6

At 1845 zone time, on 17 March, while taking stars for an evening fix, you observe an unidentified star bearing 200° T at an observed altitude of 53° 45.0'. Your DR position at the time of the sight is LAT 25° 10.0' N, LONG 66° 48.0' W. The chronometer time of the sight is 10h 47m 49s, and the chronometer error is 1m 54s fast. Your vessel is steaming on a course of 290° T at a speed of 18.0 knots. What star did you observe?

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Question 1 of 29218
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At 1845 zone time, on 17 March, while taking stars for an evening fix, you observe an unidentified star bearing 200° T at an observed altitude of 53° 45.0'. Your DR position at the time of the sight is LAT 25° 10.0' N, LONG 66° 48.0' W. The chronometer time of the sight is 10h 47m 49s, and the chronometer error is 1m 54s fast. Your vessel is steaming on a course of 290° T at a speed of 18.0 knots. What star did you observe?

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🔍 Key Concepts

• Intercept and azimuth method for star identification • Using chronometer time and chronometer error to find correct UTC/GMT • Relationship between a star’s azimuth and altitude and its position relative to your DR latitude and longitude

💭 Think About

• First, convert the chronometer reading with its error into the correct GMT and then into GHA/Dec for candidate stars at that instant. What key time conversions do you need to verify? • Think about your DR latitude and the observed altitude of about 54°. Does that altitude suggest a star with a declination closer to your latitude, much higher, or in the opposite hemisphere? • Compare the true bearing 200° T of the star with the expected azimuths of each candidate star for your DR position and time. Which one would lie roughly on that bearing from your ship?

✅ Before You Answer

• Confirm you applied the chronometer error (fast/slow) in the correct direction when finding GMT. • Check whether each candidate star’s declination makes sense for an observed altitude of 53° 45.0' from LAT 25° 10.0' N. • Ensure the star’s computed azimuth is close to 200° T for your DR position and the corrected time before choosing among the options.