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: Lies, damn lies, and statistics...
    From: Hewitt Schlereth
    Date: 2013 Mar 19, 12:33 -0700

    That was my normal practice, too, Tom. Take the two brightest things in the 
    twilight (other than an Airbus) with a decent bearing spread and get a 
    handful of sights of each. Time is limited at dawn and dusk. Better to get 
    three each of two than one each of three.
    
    Hewitt
    
    
    Sent from my iPad
    
    On Mar 19, 2013, at 6:33 AM, "Tom Sult"  wrote:
    
    > In real world CelNav One generally shoots the same star 3 to 5 times in  
    succession followed by the second star 3 to 5 times in rapid succession. This 
    increases the confidence in each site. One can graph these sites and throw 
    out any outliers and even take a time average sites from the data.  I may 
    have too much Neanderthals blood to understand statistics but...
    > 
    > Tom Sult
    > Sent from my iPhone
    > 
    > On Mar 19, 2013, at 4:56, Jeremy C  wrote:
    > 
    >> 
    >> Gary,
    >> 
    >> I would qualify this. Make sure that you have high confidence in those two 
    lines you shoot. I can "feel" when a line is good when I shoot it. I hope 
    that others do as well. I therefore weigh those LOP's much heavier than 
    others. If you shoot 2 LOP's (be them celestial or terrestrial) and you muck 
    one of them up, you can be way off.
    >> 
    >> I am one of those people who don't know statistics except in the broadest 
    of terms. To compensate for this at sea, I remind myself that the celestial 
    fix is approximate at best, and I know about what error of position I can 
    expect based on the stars I manage to observe and the environmental 
    conditions present at the time.
    >> 
    >> This same concept flows through my thinking on all fixes. Celestial being 
    the least accurate, followed by visual bearings, then radar ranges, and 
    finally GNSS which can be further subdivided by things such as WAAS, DGPS, or 
    multi-system (L2) receivers.
    >> 
    >> While I applaud people's efforts to use statistics to boost fix confidence, 
    I am well aware of the limits of precision and accuracy of the various means 
    to determine position.
    >> 
    >> Jeremy
    >> ----------------------------------------------------------------
    >> 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
    >> ----------------------------------------------------------------
    >> 
    >> View and reply to this message: http://fer3.com/arc/m2.aspx?i=122952
    > 
    > 
    > View and reply to this message: http://fer3.com/arc/m2.aspx?i=122953
    > 
    > 
    

       
    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