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: Lunars and accuracy generally: ad hominem remarks.
    From: Brad Morris
    Date: 2013 Jan 3, 21:18 -0500


    I also felt a bit put off when you mentioned the know nothing know it alls, particularly in respect to a 10 mile window.

    I used that number to show the effect of a 10 mile error with regards to an ocean crossing of thousands of miles AND how being inside or outside a cocked hat made little difference in the grander scheme of things.

    It _appears_ as if you seem to think I'm a know nothing know it all.  Was that really your intention? 

    Gee whiz, I may not know everything about naviation.  In fact I have readily admitted I'm not an expert at all.  I'm still learning, thanks to the list.  But a know nothing know it all??? A bit harsh.

    Brad Morris

    On Jan 3, 2013 2:48 PM, "Bill Morris" <engineer@clear.net.nz> wrote:


    "I received an email from a former NavList member, a couple of days ago."

    I think you erred in replying publicly to a private post. You may have felt that you were being accused of fraud because he said he didn't believe you. Would you have reacted the same way if he had said "Your results are simply incredible"? At any rate, you know the author's style, his message was directed at you, was private and should have stayed that way.

    "Others will surely know that this was from that most miserable of online character-types, a "know-nothing know-it-all". He ranted about the accuracy of lunars in October 2010 but based his conclusions on incompetence at every level: in his observations and in his calculations, too.

    Nonetheless, I post this because I think it's an interesting expression of the degeneracy into which celestial navigation has fallen. There are people who are so incompetent at adjusting and using their sextants and working even the simplest of calculations..."

    I have commented (twice) before about ad hominem remarks on the list and the possible effects on potential members. It may be that a majority of present members do not know how to manipulate statistics, many do not know how to adjust and use their sextants _properly_ and a sizable minority may have some difficulties with calculation. Your remarks may deter them from finding out more by posting queries.

    "...that they actually do not believe it is physically possible to measure angles with a standard deviation of a quarter of a minute of arc."

    It is easy for those with little statistical knowledge to get from this remark that you are claiming an _accuracy_ of this order when in fact you are saying that the dispersion of an unstated number of your results about an unstated mean is of a particular pattern. Not everyone will get that it conveys the idea of consistency rather than accuracy.

    For what it is worth, I got a closely similar standard deviation (0.23', n = 60) yesterday when assessing the SD of index errors of a sextant using a 7 x 30 monocular. My neck does not allow a similar exercise with the Sun and the Moon.

    Bill Morris
    New Zealand

    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

    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