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: Compare Methods: Lat/Lon Near Noon
    From: Frederick Curtis
    Date: 2021 Sep 1, 17:45 -0700

    In answer to Frank Reed's question.

    Eldridge's Tide Tables includes a page of the Sun's declination for the year and another of the times of Local Apparent Noon, 2018 scans attached.

    Eyeballing the rough sight data I mentally estimated the time of the Sun passing over our meridian as after 16-37-30 and before 16-38-00 since the Sun crossed the Greenwich Meridian at 11-56-41 I subracted that time from 16-37-41 for ease of calculation giving our meridian as approximately 4hrs-41minutes which multiplyed by 15 degrees gives a longitude of 70°15'.

    As my father, who admittedly was not a navigator but who was a scientist, would have said "that puts us within spitting distance."

    Around 1989 I was rocking and rolling on an exposed Parks-Canada mooring bouy on the St. Lawrence River playing with a die-cast WWII emergency sextant I had picked up for a couple dollars in the flea market of the Clayton Antique Boat Show. Seeing that I was also using a scientific calculator along with it the gentleman on the adjacent mooring asked how accurate the readings were. When I told him it was giving me plus or minus about twelve miles he informed us he was a retired Royal Navy Captain and that was as good as he ever expected at sea.  

    By the way I have clipped out four years worth of these ephemeris from Eldridge enclosed them in plastic liners and carry them in my sextant case along with a copy of Bayless' version of H.O. 211.  Wouldn't the Boy Scouts love me being prepared?



    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