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: Point Venus, May 1774
    From: George Huxtable
    Date: 2007 Apr 29, 18:09 +0100

    Alex wrote on 25 April  about Cook on Tahiti
    
    | My calculation outlined in the previous message implies
    | that the going of the Clock from May 2 to May 6 was
    | approx 22m33sec per day.
    
    I think Alex has corrected those numbers in a later message.
    
    | What sort of "astronomical clock" was this, I don't know.
    | And why did not they use chronometers instead.
    
    Cook didn't have a chronometer, on this, his first voyage. Anyway, on land,
    a good pendulum clock, compensated for temperature (gridiron) and calibrated
    against sky objects, should be better than any early chronometer.
    |
    | 2. Moon's altitude. Here something happens that I cannot
    | understand. The average error in Moon's altitude
    | was +6' on May 2 (average of 5)
    | and +7'8 on May 6.
    | The stated Index errors were +1' and +3', respectively.
    | Which leaves us with unaccounted 5'.
    | The only plausible explanation I have for this 5'
    | is that they had a substantial dip, which they did not record
    | in their account...
    
    When you are comparing Cook's altitude observations, what times are you
    using? Remember, he used apparent time, as did the Almanac then, whereas
    modern calculations expect GMT. Has that been taken into account?
    
    George.
    
    contact George Huxtable at george---.u-net.com
    or at +44 1865 820222 (from UK, 01865 820222)
    or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    
    
    --~--~---------~--~----~------------~-------~--~----~
    To post to this group, send email to NavList@fer3.com
    To unsubscribe, send email to NavList-unsubscribe@fer3.com
    -~----------~----~----~----~------~----~------~--~---
    
    

       
    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