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: First plot!
    From: David Pike
    Date: 2022 Jun 19, 15:01 -0700

    Hello Joe
    Nice ship model.  Did you make it?  Tight fix.    It’s difficult to say much more without a photograph of the sheet under your plot; the type of sextant you were using and the time of your observations.  As far as I can see, if your sights were all of the Sun, they must have been several hours apart at approximately morning, early afternoon, and later in the afternoon.    

    HO249 is good enough for sights taken with aircraft sextants.  If you were using the periscopic Kollsman you spoke of earlier, don’t expect the precision and repeatability of a marine sextant.  You only need look at an exploded drawing of an aircraft sextant with all the opportunities for backlash and differential expansion to see why.  Last week I was talking to the Nav-Plotter from the RAF Vulcan crew which beat the 30 odd B52s in the 197? SAC Annual Navigation Competition.  Their winning final position at the end of the celestial stage was 3.5nm, and that was considered remarkable at the time.  I know they were flying at 480kts, buy it makes the point.  DaveP

    P.S. After typing the above I read Al Stuart’s post giving your spreadsheet.  I only looked at the bubble sight in detail.  It confused me a bit, because you’d talked of using HO249, but your intercept in the spreadsheet was from your DR Position, not your assumed position of 36°N 140° 11'W to give LHA = 009°, which you show in your diagram.  I used AP3270 Vol 2 (HO249) to get 26’ towards, which agrees with your diagram. Sorry for the splodges; I’ve not done it for a bit, especially for easterly longitudes.


    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