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
    Noon sun fix example
    From: Jeremy C
    Date: 2009 Sep 17, 19:52 EDT
    I shot a "Wilson-esque" sun around noon with the worse possible combination that I could get here on this voyage. Basically we were heading CRS 305 spd 7.6 knots (sailboat speed) in the middle latitudes (32 deg North) with the sun descending towards the celestial equator at 1.1' per hour and a declination around 3 degrees North.
    Instead of a 30 line spread over 30 minutes as I have done in the past, I tried a far more likely, and simple approach: 5 LOP's 2 before LAN, one "at" LAN, and two after.  They are shot as nearly equal intervals around LAN (within a few seconds).  They are nearly equal altitudes to boot, which was unintentional as I was taking them by time not by arc.
    I plotted the lines by standard trig reduction on the computer and gave a very reasonable fix error at 1300 of 0.3 nm.
    Here's the data.
    Height of eye 103 feet
    Index correction -1.2'  (IE 1.2' on the arc)
    Standard Temp & pressure
    Sun, all lower limb observations.
    Crs 305 deg True
    Spd 7.6 knots
    ZD +4
    15 September 2009
    GPS fix at 1300 Lat 32 deg 4.7' North; Long 075 deg 33.1' W
    Time (LT)         Hs
    12h 47m 45s    60 deg 33.8'
    12h 52m 17s    60 deg 37.6'
    12h 56m 48s    60 deg 38.4'
    13h 00m 17s    60 deg 37.4'
    13h 05m 48s    60 deg 33.4'
    Find the 1300 fix by observation.  (please attach any graphs if that is the method of solving)

    NavList message boards: www.fer3.com/arc
    Or post by email to: NavList@fer3.com
    To unsubscribe, email NavList-unsubscribe@fer3.com

    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