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
    Digital watches as chronometers
    From: Gary LaPook
    Date: 2020 Oct 28, 01:37 -0700

    This is another update on my experiment using three cheap, $17.00,
    watches as a chronometer.

    I obtained another set of data today, October 28, 2020 Z at
    0602 Z, 4058 days since the start, more than ELEVEN YEARS
    See attached photo taken at 06:02:28Z,

    watch "A" is 16 minutes and 42 seconds fast, etc. (The seconds
    are in the top windows.)
    I have not had to replace any of the batteries in ELEVEN YEARS.

    At the beginning of this experiment I determined the daily rate of
    each watch from a 99 day sample. Watch "A" has a rate
    of 0.1919 seconds fast per day; watch "B", 0.3737 fast; and watch
    "C" is 0.6263 fast. Using these values I calculated what the
    predicted corrections would be, the values that would be
    used by the navigator to correct the chronometer time,
     and compared with the measured values.
    The differences show how much of a navigational error would have
     resulted from the navigator using the predicted times.

    In the format for A, B, and C in seconds: actual error;
    predicted error; difference.


    A = 1002/825/177 fast: B = 1483/1539/56 slow: C = 2569/2601/32 slow

    Averaging these differences equals 30 seconds fast.

    Using only one watch with the largest error, 177 seconds, would
    resulted in a 44 minute of longitude error. Using the average of
    all three watches would have produced an error of only 7.4 minutes
    of longitude, not bad for fifty-one dollars worth of watches
    after more than ELEVEN YEARS.
    ============================================
    Prior update:

    This is another update on my experiment using three cheap, $17.00,
    watches as a chronometer.

    I obtained another set of data today, May 31, 2013 Z at
    0108 Z, 1351 days since the start, more than three years
    and eight months. See attached photo taken at 01:08:00Z,
    (WWV radio signal)
    watch "A" is 5 minutes and 6 seconds fast, etc. (The seconds
    are in the top windows.)
    I have not had to replace any of the batteries.

    At the beginning of this experiment I determined the daily rate of
    each watch from a 99 day sample. Watch "A" has a rate 
    of 0.1919 seconds fast per day; watch "B", 0.3737 fast; and watch
    "C" is 0.6263 fast. Using these values I calculated what the 
    predicted corrections would be, the values that would be
    used by the navigator to
     correct the chronometer time,
     and compared with the measured values.
    The differences show how much of a navigational error would have
     resulted from the navigator using the predicted times.
    
    

    In the format for A, B, and C in seconds: actual error;
    predicted error; difference.


    A = 306/266/+40 fast: B = 528/536/ -8 slow: C = 906/846/-20 slow

    Averaging these differences equals 4 seconds fast.

    Using only one watch with the largest error, 40 seconds, would
    resulted in a 10 minute of longitude error. Using the average of
    all three watches would have produced an error of only one minute
    of longitude, not bad for fifty-one dollars worth of watches
    after more than three and a half years.

    See my prior reports at:

    http://fer3.com/arc/m2.aspx/Watches-chronometers-LaPook-oct-2011-g17175

    File:


       
    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