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: Scrap paper with time sights c.1870
    From: Lars Bergman
    Date: 2013 Feb 24, 15:15 -0800

    I have done some more research into the twenty longitude observations provided by Frank. Searching through various editons of Bowditch I haven't found one with a really good fit, either they are out in declination or in equation of time. In order to fit, the December observations must have been made in a year before a leap year, and thus the January observations in a leap year. A further search through various American Ephemeris and Nautical Almanacs has got me back to December 1855 and January 1856. Checking all observations against these years makes a very good match, all declination values are spot on except one, which is 1 minute of arc off. Of the EoT-values I have found 6 to be off, but no more than 1 second, or in same cases rather half a second. The others are spot on. So my opinion is (today at least ...) that the voyage was made during the winter 1855-1856, and that an American NA was carried on board.

    To be honest, I have not checked possible years before 1855, or after 1899.

    Frank, you wrote: "There is ... another sheet of scrap paper, probably from the same voyage, with about sixty more time sights. Would anyone like to see those?"

    Yes, that would be interesting!

    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

    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