Emergency Navigation Quiz Global Navigation Chapter 7 1

Question 1 A vessel travels 30 nm on course 045° from L 30° 32' N, Lo 40° 43' W. What is the approximate latitude and longitude at the point of arrival? n Réponse : L 30° 53’N, Lo 040° 20’W 2

Question 2 29 october n Since your latitude = Sirius n. From the Nautical Almanac, you find that the GHA Aries 1500 hour 263° 16, 6’ Solution: n 29 october n UT 15 -14 -58 on 29 October n At To obtain longitude, calculate the GHA declination, your latitude is n. SHA Sirius is 258° 39, 6’, and its declination is 14 m 58 s 3° 45, 1’ n Since Sirius is directly overhead, you are n Since GHA<180°, GHA = Lo W, so your Sirius at the time of the sighting: approximately L 16° 43, 0’S. 20 XX, you identify Sirius directly 16° 43, 0’S. at GP of the body. To find your latitude n longitude is approximately Lo 165° 41, 3’W. n GHA Sirius = GHA (Aries) + SHA overhead. What is your position ? and longitude, convert Sirius’ celestial n GHA Aries 15 -14 -58 267° 01, 7’ (Arcturus) coordinates for that date and time to n 258° 39, 6’ SHA Sirius terrestrial coordinates. Answer : L 16° 43, 0’, Lo 165° 41, 3’W. n Sub-total 525° 41, 3’ n UT 15 -14 -58 29 october - 360° n GHA Sirius 165° 41, 3’ n 3

Emergency Navigation Quiz End of Global Navigation Chapter 7 4