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    Lat & Lon by Before and After LAN Ex-Meridians
    From: Greg Rudzinski
    Date: 2011 Nov 20, 17:14 -0800

    Data from Stan's Flint Island celestial navigation problem is used in solving latitude and longitude by before and after ex-meridian observations.

    Ex-meridian reduction by Bowditch table 29 and formula a(t^2)/60

    Before XM: UT 21H59M00S (+8M44S) UT 22H7M44S LAN
    After XM: UT 22H13M27S (-5M43S) UT 22H7M44S LAN
    Time difference 14M27S Long. 151* 49.6' W

    a=8.5 (table 29)
    XM Before: 8.5(8.7)(8.7)/60= +10.7'corr. Lat. 11* 15.6'+10.7' = 11* 26.3' S
    XM After : 8.5(5.7)(5.7)/60= + 4.6'corr. Lat. 11* 21.6'+ 4.6' = 11* 26.2' S

    Time trial iterations were used for best fit time to meridional passage getting an equal latitude result.
    An equation can do this better. Math experts needed here.

    Greg Rudzinski


    I have been teaching the Power Squadrons Navigation and Junior Navigation courses for quite a while now, but I started teaching the "new" Junior Navigation course for the first time in September. The course is quite a bit watered down compared to the "old" course, with the sun being the only body of interest. In the past I created or borrowed what I call SuperNavigator problems for the students, generally a bit beyond the scope of the material, but requiring the students to do some thinking rather than just plugging in numbers.

    Due to the limited amount of material in the new course, I think I was able to incorporate all aspects of celestial navigation included in the course into one SuperNavigator problem, which I have attached, along with the one page of the 1972 Nautical Almanac required. I have not included my solution, for fear of making a fool of myself . I would appreciate it if you would take a look at it and tell me if you think it makes sense and is reasonable. I think the intermediate answers require the students to prove they have a real understanding of the material more than the final answer does, but I would like to know what you think.

    Thanks for your support.

    Stan
    Attached File: 117427.supernavigator noon fix rev. b problem.doc (no thumbnail available)
    Attached File:


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