Welcome to the NavList Message Boards.


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

Compose Your Message

Add Images & Files
    Re: First Moon-Star Lunar
    From: Sean C
    Date: 2017 Dec 28, 03:26 -0800


    FWIW, I tried working your lunar using Frank's fomulae and your data. I got slightly different values for the SD of the Moon & the "dh"s and a very different value for "Q". My figures (differences in bold) are:

    SD Moon = 0.2724 ∙ 0°55.2' = 0°15.0'

    Aug. SD = 0°00.3' ∙ sin(37°50.1') = 0°0.2'

    Total SD = 0°15.2'

    "LDpc" = 95°53.8' - 0°15.2' = 95°38.6'

    dh_Moon = -0.0167°/tan(37°50.1'+7.32°/(37°50.1'+4.32°)) + 0°55.2' ∙ sin(37°50.1') = 0°42.3'

    dh_Star = -0.0167°/tan(36°10.7'+7.32°/(36°10.7'+4.32°)) = -0°1.4'

    A = 0.828

    B = 0.836

    Q = (0.55 ∙ (0°42.3')^2 ∙ cot(95°38.6') ∙ (1 - 0.828^2)) / 3438 = -2.47E-6

    "LDc" = 95°04.8'

    LD at 0000 UT = 95°07.8'

    LD at 0100 UT = 94°37.0'

    Interpolating, I get an "observed time" of 00:05:50.6. This is just -3.4 seconds difference from the actual time of 00:05:54. I did reverse the signs of dh_Moon & dh_Star when doing the final clearing calculation. Also, you can see that I am calculating these terms instead of looking them up in the N.A.

    What confuses me most is the difference in the value of "Q". Your figure of 0.15' is very different than the -0.0089" that I arrived at. Perhaps I am doing something wrong. (Frank, care to chime in?)

    In any case, congratulations on a very well done lunar!


    Sean C.

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    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 Settings

    Posting Code:

    Custom Index

    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