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
    Name or NavList Code:
    Re: How Many Chronometers?
    From: Brad Morris
    Date: 2009 May 6, 13:22 -0400

    This is an interesting question.
    If you know your latitude and longitude, then you can fit your chronometer to 
    the known altitude.  If the altitude is wrong for the time, then you can 
    adjust the chronometer error as a function of the longitude you find.  A 
    lunar observation can be solved, with a known position, to adjust the 
    chronometer error.  In fact, for a known position, many different 
    observations can be used.  The only requirement is that time is parameter 
    when solving for a known position.
    Apparent time at sea may be found by Von Littrow, Bowditch and others, but I 
    do not believe this recovers GMT or UT.
    But your question is, I think, recovering time when at sea, using only 
    chronometers.  I have read about expeditions that kept as many as 22 
    chronometers, when on survey expeditions (the name escapes me).  In this 
    circumstance, voting will permit the accurate recovery.
    Best Regards
    -----Original Message-----
    From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Greg Rudzinski
    Sent: Wednesday, May 06, 2009 1:11 PM
    To: NavList
    Subject: [NavList 8157] How Many Chronometers?
         When a time tick or other master reference is not available then
    by what means can a navigator at sea use to determine whether a
    chronometer is maintaining a consistent rate. If two chronometers are
    carried then an inconsistency between the two would suggest a problem
    but then which chronometer is at fault? How about a third chronometer
    to help the navigator determine which chronometer is behaving badly.
    Carrying three chronometers does triple the chances of one going down
    but since quartz watches are cheap why not carry three?
    "Confidentiality and Privilege Notice
    The information transmitted by this electronic mail (and any attachments) is 
    being sent by or on behalf of Tactronics; it is intended for the exclusive 
    use of the addressee named above and may constitute information that is 
    privileged or confidential or otherwise legally exempt from disclosure. If 
    you are not the addressee or an employee or agent responsible for delivering 
    this message to same, you are not authorized to retain, read, copy or 
    disseminate this electronic mail (or any attachments) or any part thereof. If 
    you have received this electronic mail (and any attachments) in error, please 
    call us immediately and send written confirmation that same has been deleted 
    from your system. Thank you."
    Navigation List archive: www.fer3.com/arc
    To post, email NavList@fer3.com
    To , email NavList-@fer3.com

    Browse Files

    Drop Files


    What is NavList?

    Get a NavList ID Code

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    A NavList ID Code guarantees your identity in NavList posts and allows faster posting of messages.

    Retrieve a NavList ID Code

    Enter the email address associated with your NavList messages. Your NavList code will be emailed to you immediately.

    Email Settings

    NavList ID 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