On 22 March your 1834 DR position is LAT...

Question 1 of 31048ISLE6fldIZBNOhGcdCkc

On 22 March your 1834 DR position is LAT 26°13.5'S, LONG 108°36.5'W. You observe an unidentified star bearing 062°T at an observed altitude (Ho) of 23°22.0'. The chronometer reads 01h 32m 37s, and is 01m 50s slow. Which star did you observe?

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Question 1 of 31048

🔍 Key Concepts

• Chronometer correction and GMT – Convert the given chronometer time and error into correct Greenwich Mean Time (UTC) for the sight. • Approximate Local Hour Angle (LHA) of Aries – Use the date and corrected GMT with your DR longitude to find a rough LHA Aries for the sight reduction. • Star identification logic – From the bearing (062°T) and altitude (23°22.0'), estimate the star’s azimuth quadrant and declination/SH, then compare those with typical positions of the candidate stars.

💭 Think About

• First, correct the chronometer time using the given error. What is the correct GMT of observation, and what is the corresponding GHA of Aries on 22 March around that time? • Using your DR longitude, what is your approximate LHA Aries? From that, what sidereal hour angle (SHA) and declination would a star in that azimuth/altitude region likely have? • Which of the four stars has a declination and SHA that fit a star seen at low altitude in the SE to ENE sector from a vessel at about 26°S on that date and time?

✅ Before You Answer

• Be sure you apply the chronometer error with correct sign ("slow" vs "fast"). • Check the hemisphere and quadrant: from 26°S and bearing 062°T, is the star in the NE, SE, NW, or SW part of the sky? • Verify which candidate stars have declinations visible from 26°S and which would plausibly give an Ho near 23° at that azimuth.