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: Need help writing a slope-fit excel sheet
    From: Peter Hakel
    Date: 2014 Jan 24, 19:15 -0800
    Hello Greg,

    Please take a look at these links:


    What I describe there is different, because in my spreadsheets the fits are computed rather than guided by eye looking at a plot.  Nevertheless, it is related to what you are trying to do, so you may find it useful.

    A few years ago we had extensive discussions on NavList about precisely this topic.  You may use NavList's search engine (thanks, Frank!) to look for threads named "Kurtosis", "Weighted least squares", and "Rejecting outliers" which started around December 2010.

    Peter Hakel

    From: Greg Licfi <cfi@licfi.com>
    To: pmh099@yahoo.com
    Sent: Friday, January 24, 2014 6:03 PM
    Subject: [NavList] Need help writing a slope-fit excel sheet

    Hi all,
          I read a article by David Burch concerning sight averaging with (I
    believe) the intent on improving
    the sights taken with plastic sextants. Mr. Burch believes that this
    technique should be applied to metal
    sextants to improve overall accuracy. One of the things he suggested is
    doing a slope-fit of the multiple
    sight data to kick out not-so-obviously-bad data points. It all makes
    sense to me. I started to write a slope-fit
    excel sheet (which eventually I can use on my smart phone) There are two
    plots: one is the sight data
    in BLUE, the second is a Hc for the start & stop times of the sights it
    is in RED. ultimately you will be able to
    slide the RED Hc plot up or down to see if the sight data points fit the
    slope. I'm stuck getting the buttons
    to work. I would ask if there are any excel mavens on the list if they
    could look at my attached sheet and
    help me activate the cursor up/down buttons; I'm not super knowledgeable
    on macros. Once that is figured
    out it should be quite handy for isolating bad sights.
    Many Thanks In Advance!
    Typically how many sights on average should one take, and over what time
    Attached File:

    (img/126689.slope fit.xls: Open and save or View online)

    View and reply to this message: http://fer3.com/arc/m2.aspx?i=126689

    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