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
    Constructing the axes of the sum of squares ellipse
    From: Bill Lionheart
    Date: 2019 Apr 9, 03:18 -0700

    I have been trying to make some videos of ruler and compasses constructions.

    The symmedian point is fairly well known on this list. This is the best unbiased linear estimate assuming zero mean identically distributed uncorrelated errors for three lines of position.  It is also tha maximum of the probability if in addition teh errors are assumed Gaussian. So the next step is to construct something that helps understand the family of ellipses with constant sum of squared distance to the lines. In this video I constrict the major and minor axes of the ellipses, using the fact that the major axis goes through the incentre of similitude of the orthocentric and circumcentric circles, the triangle centre numbered X(1344) on Kimberling's Encyclopedia of Triangle Centres.


    Let me know what you think. I am still not good at making these videos. I have got a better pair of compasses and some coloured pencils and that will make it a bit clearer if I have another go.

    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