NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Ron Jones
Date: 2018 Aug 20, 12:28 -0700
Navigation Quiz
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_____________ , Dec ____________, Ho_______________
For the Altar what is Total GHA_____________ , Dec ____________, Ho_______________
For the Antares what is Total GHA_____________ , Dec ____________, Ho_______________
For the Arcturus what is Total GHA_____________ , Dec ____________, Ho_______________
For the Rigel Kentarus what is Total GHA_____________ , Dec ____________, Ho_______________
Which bodies provide the best 2 body fix? _________________, ________________
Which bodies provide the best 3 body fix? ________________, ________________, ________________
What was your latitude & longitude @ 19:20:00 GMT for the 2 body fix? _____________, ___________
What was your latitude & longitude @ 19:20:00 GMT for the 3 body fix? _____________, ___________
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? _________________,_____________
(See Nautical Almanac Page 282 paragraph 11)
What island did you spot to the North West just prior to sun set? ________________________