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    Re: Where in the world?
    From: Ron Jones
    Date: 2018 Aug 23, 17:28 -0700

    Quiz Answers for "Where in the world"

    You & four friends (Tom, Bob, Don & Rick) are on a cruise ship.  Each of you brought along your marine sextants, 2018 Nautical Almanacs, Texas Instruments Voyage 200 calculators and plotting materials to practice your celestial navigation skills.  On August 17th 2018 just before sun set you spot a small island to the North West of your position.  At 19:20:00 GMT using your sextant to measure the altitude of the Moon’s lower limb, you find the sextant altitude to be 75°  18.5’.  At the same time Tom measures the altitude for Antares and gets a sextant altitude of 71° 22.4’,  Bob obtains a sextant altitude for Rigel Kentarus of  35° 22.7’, Don obtains a sextant altitude for Altar of  31° 37.9’ & Rick  obtains a sextant altitude for Arcturus of  51° 25.2’. Previously you had determined the upper observation deck of the cruise ship to be 88 feet above the water line.  Your sextant’s index correction, IC= -1.6’, Tom’s IC= -1.8’,  Bob’s IC= -0.3’, Don’s IC= -0.4’ & Rick’s IC= -2.1’.  The air temperature is 31°C & the pressure is 1005mb.

    Nautical Almanac data for August 17th 2018 for GMT = 19:00:00

    Moon GHA =23° 32.8’ v=12.2 Dec 12° 24.1’ S  d=9.2 HP=56.3’  Moon’s declination is increasing with time

    Aries GHA=251° 06.2’

    Altar                      SHA=062° 04.5’  Dec=08° 55.3’ N

    Antares                SHA=112° 21.9’  Dec=26° 28.2’ S

    Arcturus               SHA=145° 52.7’  Dec=19° 05.5’ N

    Rigel Kentarus   SHA=139° 47.1’  Dec=60° 54.7’ S


    For the Moon                what is Total GHA _28°_23.3’_ __ , Dec _12°_27.2’ S__, Ho___75°  37.4’____

    For the Altar                  what is Total GHA__318° 11.5’___ , Dec _8° 55.3’ N  _ , Ho___31° 26.9’____

    For the Antares             what is Total GHA__    8°  28.9’___ , Dec _26°  28.2’ S_,  Ho___71°  11.2’____

    For the Arcturus            what is Total GHA__ 41° 59.7’_  _ , Dec _ 19° 5.5’ N__,  Ho___51° 13.3’____                                      

    For the Rigel Kentarus  what is Total GHA__35° 54.1’___ , Dec __60° 54.7’ S_,  Ho___35° 12.0____

    Which bodies provide the best 2 body fix? __Moon_____,  ___Antares_____

    Which bodies provide the best 3 body fix? __Altar______, __Arcturus_____, __Rigel Kentarus __

    What was your latitude & longitude @ 19:20:00 GMT for the 2 body fix? _8° 29.7’ S_, _14° 19.6’ W__

    What was your latitude & longitude @ 19:20:00 GMT for the 3 body fix? _8° 29.9’ S_, _14° 19.7’ W__

    What was your latitude & longitude @ 19:20:00 GMT for a 5 body fix using the method for determining position from intercept and azimuth by calculation? ___8° 29.7’ S_, _14° 19.7’ W __  
                                                                                                        (See Nautical Almanac Page 282 paragraph 11)

    What island did you spot to the North West just prior to sun set? ___ Ascension _________

    Note: The 2 body & 3 body fix was found using the intersections of Circles of Equal Altitude

    See attached PDF for details.

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