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: "100 Problems in Celestial Navigation"
    From: Herbert Prinz
    Date: 2004 Apr 2, 01:30 -0500

    Renee Mattie wrote:
    
    > I'm having problems with "100 Problems"
    > [...] after working the first 6 problems, I am finding myself 5-10 miles
    > away from the
    > author most of the time.
    
    Renee,
    
    I reduced problem 1-6 with a computer program and obtained a fix at N 40
    09.6 W 046 5.2 where Gray gets N 40 09 W 46 04.
    
    A difference of 1 mile in each coordinate is too high to blame it on
    different sight reduction methods. More likely, the difference comes from a
    bad estimate or an arbitrary choice of the MPP (most probable position)
    within the cocked hat. Since the cocked hat consists of 6 lines it is
    difficult to guess the MPP from the geometry of the LOPs.
    
    However, 5 miles difference indicates an error. I notice that Gray
    specifies index correction, not index error. Did you get this right? A
    confusion of this kind can easily throw you off by 5 miles.
    
    Post your results for problem 1-6 (DR, intercepts and azimuths of
    individual LOPs), then we can discuss them. Those who think that particular
    sight reduction methods can lead to a result 5 miles off are invited to
    demonstrate them to us so that we can avoid these methods in the future.
    
    Herbert Prinz
    
    
    

       
    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