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19. The Complete Day’s Work

19. The Complete Day’s Work. Presented By: Kelly Curtin, Asst. Professor. Course Outline. Navigational Astronomy Lecture 1 & 2 Mean Time / Apparent Time Lecture 3 Time Zones, Zone Description, Chronometer Time Lecture 4

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19. The Complete Day’s Work

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  1. 19. The Complete Day’s Work Presented By: Kelly Curtin, Asst. Professor

  2. Course Outline • Navigational Astronomy Lecture 1 & 2 • Mean Time / Apparent Time Lecture 3 • Time Zones, Zone Description, Chronometer Time Lecture 4 • The Earth, Celestial, And Horizon Coordinate System Lecture 5 & 6 • The Spherical Triangle Lecture 7 • Circle of Equal Altitude Intercept Lecture 8 • Time Diagram, Right Ascension Lecture 9 • The Nautical Almanac, Finding GHA, LHA, and Dec. Lecture 10 & 11 • Instruments For Celestial Navigation Lecture 12 • Sight Reduction of the Sun, Stars, Planets, Moon Lecture 13 - 15 • Plotting and Advancing / Retarding the Assumed Position Lecture 16 • Calculating Time of Meridian Passage (LAN) Lecture 17 • Calculating Latitude at Meridian Passage Lecture 18 • Calculating Time of Sunrise/ Sunset/ Twilight Lecture 19 • Star Shooting Schedule / Pub. 249 Lecture 20 • Azimuth and Amplitudes Lecture 21 – 24 • Polaris – Azimuth and Latitude By Lecture 25 • Star – Finder – Stars, Planets, Selecting the 3 best Stars Lecture 26 • The Complete Day’s Work Lecture 27 & 28

  3. Days Work Requirements IXX: Complete Day’s Work - Plotting EXAMPLE OF A DAYS WORK PLOT

  4. Days Work Requirements IXX: Complete Day’s Work - Plotting • The following calculations are what would normally be required for a ½ day’s work – AM calculations only. • The Date is 19 September 1981, your 0300 zone time position is Lat. 24° 35.0’N, Long. 088° 40’W. You are on course 288°T • at a speed of 14 knots. • 1. Pre-compute Star-Time and list the 7 selected stars from Pub. 249 • 2. The following stars are observed during Star-Time: • Body Zone Time Hs • Regulus 0530 22° 56.9’ • Sirius 0532 44° 41.0’ • Hamal 0536 43° 26.9’ • The index error is 2.0’ on the arc and your height of eye is 58 feet. What are the Latitude and Longitude of your 0600 R-Fix? • 3. Just after sunrise at 0550-00s you observe an amplitude of the sun on the celestial horizon, The sun is bearing 089.5° PGC. • What is the Gyro Error? You perform a compass check and the vessel is heading 289° PGC and 283° PSC. • If the variation in the area is 8°E, What is the deviation of the magnetic compass on this heading? • 4. After the watch is relieved at 0815-36s an azimuth of the sun is observed. The sun is bearing 106° PGC. • What is the Gyro Error now? • 5. At 0930-26 you observe the lower limb of the sun at Hs 47° 49.2’. The index error is 2.0’ on the arc and your height • of eye is 58 feet. Reduce and plot your 0930 sun line. • 6. Pre-compute the time of LAN. • 7. At 1156-45 you observe the meridian passage of the sun. The lower limb has a sextant altitude of 65° 57.0’. • The sun’s Zn is 180°. The index error is 2.0’ on the arc and your height of eye is 58 feet. What is the calculated Latitude • at LAN? Advance your 0930 LOP and your 1157 Latitude LOP to 1200 for a 1200 R-Fix. What are the Latitude and • Longitude of your 1200 R-Fix?

  5. #1: DR POS’N @ Civil Twilight 0525 DR POS’N L 24° 46’Nλ089° 14’W Sunrise Naut Civil 0455 -2 0501 -2 0459 -3 0456 0523 -1 0526 -1 0525 -3 0522 30° N 24° 46’ N 20° N 0547 -0 0548 0 0548 -3 0545 10° 6m 3m 1m 4° 46’ Correction for DLO = -3 min 46’ of Arc East of Central Meridian 90° 0509 0534 Star Time Selected Stars ZT 0509 ZD +6 GMT 1109 GHA 163° 15.7’ Inc. 2° 15.4 GHA 165° 31.1 -wλ 089° 14.0 LHA 076° 17.1’ LHA 076° @ 0508 • TIME STAR Hc Zn ∆ Hc • 0508 Cappella 68° 50’ 006° 7’ • 0512 Dubhe 22° 19’ 031° 27’ • 0516 Pollox 55° 38’ 076° 53’ • 0520 Procyon 50° 19’ 114° 50’ • 0524 Sirius 43° 23’ 151° 29’ • 0528 Rigel 56° 44’ 184° 4’ • 0532 Hamal 44° 31’ 279° 53’

  6. #2: RegulusSirius Hs 22° 56.9 i.c -2.0’ Dip -7.4’ HA 22° 47.5’ Body -2.3’ Ho 22° 45.2 Hc 23° 02.7’ Int 17.5 Adv/Ret. Adv. 7nm Hs 44° 41.0’ i.c -2.0’ Dip -7.4’ HA 44° 31.6’ Body -1.0’ Ho 44° 30.6’ Hc 44° 23.1’ Int 7.5 Adv/Ret. Adv. 6.5nm ZT 0530 ZD +6 GMT 1130 GHA 163° 15.7’ m/s 7° 31.2’ GHA 170° 46.9’ SHA* 208° 09.6’ GHA* 018° 56.5’ -west a λ 088° 56.5 LHA* 290° 00.0’ DEC 12° 03.6’ N same Alat 25° N Hct 23° 01.3 (d) (+22.5) +1.4 Hc 23° 02.7’ Z 087.1 Z Diff. (-1.0) -.1 Z 087.0 ZN 087.0 ZT 0532 ZD +6 GMT 1132 GHA 163° 15.7’ m/s 8° 01.3’ GHA 171° 17.0’ SHA* 258° 55.2’ GHA* 070° 12.2’ -west a λ 089° 12.2’ LHA* 341° 00.0’ DEC 16° 41.3’ S cont. Alat 25° N Hct 45° 00.7 (d) (-54.6) –37.6 Hc 44° 23.1’ Z 153.7 Z Diff. (+.6) +.4 Z 154.1 ZN 154.1 A T

  7. #3: Hamal Hs 43° 26.9’ i.c -2.0’ Dip -7.4’ HA 43° 17.5’ Body -1.0’ Ho 43° 16.5’ Hc 43° 43.5’ Int 27.0 Adv/Ret. Adv. 5.6nm ZT 0536 ZD +6 GMT 1136 GHA 163° 15.7’ m/s 9° 01.5’ GHA 172° 17.2’ SHA* 328° 27.9’ GHA* 140° 45.1’ -west a λ 089° 45.1’ LHA* 051° 00.0’ DEC 23° 22.5’ N same Alat 25° N Hct 43° 38.5 (d) (+13.3) +5.0 Hc 43° 43.5’ Z 081.3 Z Diff. (-1.3) -.5 Z 080.8 ZN 279.2 A Ans: 0600 R – Fix L 24° 53.0 N  089° 22.0’ W

  8. 0550 DR POS’NL 24° 51.0’ Nλ 089° 19.0’ W #3: ZT 0550 ZD +6 GMT 1150 DEC. N 1° 25.6 (d – 10) -.8 DEC. N 1° 24.8 Sin “A” = Sin Declination Cos Latitude Sin “A” = Sin 1.413 Cos 24.850 088.4 1.6° 090° Amplitude Angle “A” = 1.6° True Amplitude = E/W 1.6° N/S “A” Rising or Setting Declination True 0 = 088.4° PGC 0 = 089.5° GE = 1.1° W C D M V T GE PGC 283° 3.1°W 279.9° 8°E 287.9° 1.1°W 289°

  9. 0930 DR POS’NL 24° 58.0’ Nλ 089° 56.0’ W #4: ZT 0815 – 36s ZD +6 GMT 1415 - 36 LAT 24° 58.0’ N GHA 031° 34.2 3° 54.0 GHA 035° 28.2’ - W λ 089° 56.0’ LHA 305° 32.2’ DEC. N 1° 22.7 (-1.0) -.3 DEC. N 1° 22.4’ LHA 305° 32.2’ Dec N 1° 22.4 Lat N 24° 58.0’ Base Z 104.9 COR’N + 0.4 Z 105.3 ZN 105.3 Base Z 104.9 104.9 104.9 TAB Z 105.4 103.8 105.5 Z DIFF +/- .5 -1.1 + .6 INC. 32.2/60 22.4/60 58/60 COR’N + .27 - .41 + .58 Total + .4 True =  105.3 PGC =  106.0 GE =  .7° W

  10. 0930 DR POS’NL 25° 03.5’ Nλ 090° 14.0’ W #5: ZT 0930 - 26 ZD +6 GMT 1530 - 26 GHA 046° 34.4 7° 36.5 GHA 054° 10.9’ - W λ 090° 10.9’ LHA 324° DEC. N 1° 21.7 N (-1.0) -.5 DEC. 1° 21.2’ N HCT 305° 32.2’ (d + 36.2) 1° 22.4 Hc 24° 58.0’ Z 104.9 (Z diff)(-1.2) - 0.4 Z 105.3 ZN 105.3 Hs 47° 49.2’ I.C. - 2.0 Dip - 7.4 Ha 47° 39.8’ body + 15.1’ Ho 47° 54.9’ Hc 47° 59.2’ INT A 4.3nm

  11. #6: Pre-Compute Time of LAN 1154 DR POS’NL 25° 13.5’ Nλ 090° 50.0’ W 17H 076° 34.8’ 090° 50.0’ GMT 1751-01s ZD + 6 -6 (Rev) ZT 1151 – 01 LAN 14° 15.2’ = 51m – 01s

  12. #7: ZT 1156 - 45 ZD +6 GMT 1756 - 45 DEC. N 1° 21.7 N (-1.0) -.5 DEC. 1° 21.2’ N Hs 43° 26.9’ i.c -2.0’ Dip -7.4’ HA 43° 17.5’ Body -1.0’ Ho 43° 16.5’ ZENITH DISTANCE = (90°) 89° 60.0’ - HO 66° 03.1’ ZEN. DIST. 23° 56.9’ LATITUDE = ZEN. DIST. +/- DECLINATION = 23° 56.9’N + 1° 21.2’ N = 25° 15.8’ N 1200 LAT = +.2 25° 16.0’ N 1157 – 1200 = 3 min Dist = .7nm CHANGE IN LATITUDE = l’ = D cos C l’ = .7 cos 72° l’ = .2’ nm Ans: 1200 R – Fix L 25° 16.0 N λ 090° 49.0’ W

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