Welcome to the NavList Message Boards.

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Re: Ex-Meridian Exercise
    From: Andrés Ruiz
    Date: 2012 Jan 25, 17:44 +0100
    Hello,
    I have two books for the licence of yacht captain (1968 and 1975), that includes the ex-meridian sights.
    Spanish books differentiate between circunmeridian (t < 16 min) and ex-meridian (t >= 16 min)sights, depending on the time from meridian passage.
    Here is the example by three methods.

    15/01/2012
    10:21:00 UT1

    Geocentric equatorial coordinates
    Moon
    Dec = -9.009300 =  -9º  0.6'
    GHA = 80.077112 =  80º  4.6'

    DR
    Be = 28.666667 =  28º 40.0'
    Le = -87.166667 = -87º 10.0'

    Altitude
    Hs = 51.183333 =  51º 11.0'
    Ho = 51.788832 =  51º 47.3'

    Hs = 51.1833 º =  51º 11.0'
    ie = 0.0000 '
    heas = 0.0000 m
    T = 10.0000 ºC
    P = 1010.0000 hPa
    Hoi = 51.1833 º
    dip = 0.0000 º
    Ha = 51.1833 º =  51º 11.0'
    R = 0.0130 º
    OB = 0.00168790 º
    HP = 0.9841 º
    PA = 0.61853196 º
    SD  = 0.0000 º
    Aug = 0.00000000 º
    SDag = 0.000000 '
    Ho = 51.7888 =  51º 47.3'

    Method 1 - Latitude by Ex-meridian sight at2/60
    B = 28.579961 =  28º 34.8'
    Upper transit
    Culmination = S
    LHA = 352.910446 = 352º 54.6'

    a = 2.784005
    ma = 7.089554
    t = 28.358218
    C = 37.314413
    Hlan = 52.410739

    Method 2 - BOWDITCH 1906 (attached)
    B = 28.583413 =  28º 35.0'


    Method 3 - Newton-Raphson iterative method
     0        0.001452        0.498876        0.498876       28.583492
     1        0.000001        0.498875        0.498875       28.583413
     2        0.000000        0.498875        0.498875       28.583413
    B = 28.583413 =  28º 35.0'

    -- 
    Andrés Ruiz
    Navigational Algorithms
    http://sites.google.com/site/navigationalalgorithms/



    2012/1/23 Greg Rudzinski <gregrudzinski@yahoo.com>

    Linked image shows an ex-meridian plot crossed with a corresponding LOP using the formula (t^2)(a)/60 with a=2.8

    The Moon example is from my most recent flight from Los Angeles to Orlando. See index card working notes.


    ----------------------------------------------------------------
    NavList message boards and member settings: www.fer3.com/NavList
    Members may optionally receive posts by email.
    To cancel email delivery, send a message to NoMail[at]fer3.com
    ---------------------------------------------------------------- 

    Linked File: http://www.fer3.com/arc/imgx/f1-IMG_1040.JPG 
    Linked File: http://www.fer3.com/arc/imgx/IMG_1043.JPG 

    File:

      
       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.
    Email:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site