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: Calculator v. Slide Rule for Ex-Meridian Correction
    From: Francis Upchurch
    Date: 2016 Jan 7, 09:33 -0800

    Suggestions for cel nav linear slide rule.

    I guess one advantage of the linear is the sheer number of scales you can add. 

    On my cylindrical  Fuller, I only need the outer cylinder ( ? equivalent to A/B) and the sin scale (have added cosines in red travelling the other way). I do not need logs/log-logs etc. I can do any cel nav and nav calculations with these 3 scales.

    Perhaps the proposed linear could just have A/B ,C/D , no logs or log logs, but perhaps "stretch" the sines and cosines ( and Tan or cotan if you want to use the Bygrave formula as per Gary's suggestion) over several scales to reduce compression and increase accuracy?

    Also, one of the great advantages of the modern cheap calculator are the memories. So you can stowe an angle such as LHA, Dec, Latitude, and for the cosine formula and lunars where you use these numbers  repeatedly, either cos or sin, speeds things up immensly and reduces input keying errors. 

    Could you do this with a slide rule by having a "Degrees" scale and then separate sin/cos? You could then mark the said angle with erasable marker pen (i.e stowe it in the  memory) and line this up immediately with the sin or cosine as required?

    Just a thought.

    Francis

       
    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