Question 1 of 2921866636eea28f7522a1c51ac3a

On 20 February, your 0530 ZT DR position is LAT 24° 15.0' N, LONG 137° 33.0' W. You are on course 033° T at a speed of 18 knots. You observed three celestial bodies. Determine the latitude and longitude of your 0600 running fix.

BodyZone TimeGHAObserved altitudeDeclination
Regulus0540218° 35.9'13° 02.2'12° 03.5' N
Antares0552126° 23.5'38° 04.1'26° 23.3' S
Vega060096° 23.2'52° 33.5'38° 45.8' N
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Question 1 of 29218
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On 20 February, your 0530 ZT DR position is LAT 24° 15.0' N, LONG 137° 33.0' W. You are on course 033° T at a speed of 18 knots. You observed three celestial bodies. Determine the latitude and longitude of your 0600 running fix.

BodyZone TimeGHAObserved altitudeDeclination
Regulus0540218° 35.9'13° 02.2'12° 03.5' N
Antares0552126° 23.5'38° 04.1'26° 23.3' S
Vega060096° 23.2'52° 33.5'38° 45.8' N

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🔍 Key Concepts

• Running fix using multiple celestial LOPs (lines of position) taken at different times • How to advance or retire each LOP to the common time of 0600 using course and speed made good • Effect of DR track (033° T at 18 knots) from 0530 to each sight time on your final latitude and longitude

💭 Think About

• First, compute your DR positions at 0540, 0552, and 0600 from the 0530 DR, using the given course and speed. What DR position do you get at 0600? • Think about whether the running fix should place you slightly ahead of or behind the 0600 DR position, and whether you should be slightly more east or west based on the directions of the intercepts. • Compare each multiple-choice answer to your 0600 DR: which options are clearly too far away in latitude or longitude to be reasonable corrections from a realistic set of celestial intercepts?

✅ Before You Answer

• Be sure your time intervals from 0530 to 0540, 0552, and 0600 are correctly converted to hours and tenths of hours before you calculate distance run. • Verify the distance run from 0530 to 0600 using Distance=Speed×Time\text{Distance} = \text{Speed} \times \text{Time}Distance=Speed×Time and apply it along course 033° T to get an accurate 0600 DR position. • Check that your selected answer is within a plausible distance (a few miles) of your 0600 DR; eliminate choices that imply an unrealistically large fix correction.