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: MkIXa bubble sextant performance
    From: Jean-Philippe Planas
    Date: 2007 Apr 4, 22:41 -0700
    Hi Alex,
    Did you try to identify an Index error or any systematic error?
    Did you solve the issue of the bubble getting bigger during the observation after having been reduced when starting the observation session?

    alex <eremenko@MATH.PURDUE.EDU> wrote:

    After a month of practice, I can find my position within 2-3 miles
    with this sextant.
    The use of the averager gives better results than a single
    But averaging 5 single observations by hand gives the same precision
    as the mechanical averager does (it averages 60 observations).

    Here is a typical complete fix with the averager:
    GMT April 3, 1:28:46 Sirius 28d22' ; 1:51:55 Venus 15d18'.5
    Using DR 40N, 87W, I obtain
    Alt of Sirius 28d44'.2, Azimuth 207d,
    Alt of Venus 15d12'.8, Azymuth 282d.
    Correcting for refraction and plotting on the Universal Plotting Sheet
    gives this position 40d20'.5N, 86d54d.5W, as read from the
    plot with 0'.5 resolution.
    My true position was 40d27'.2N, 86d55.8W,
    so the error is slightly more than 1 mile.

    In this reduction I used the Complete on Board Celestial Navigator,
    which is not very precise but very handy indeed.

    Here are two typical series of individual observations (averager off,
    with the Almanac and computer).
    Venus, errors: 1'.8, -2'.4, -0'.9, -0'.2.
    Sirius, errors: 1'.2, 1'.7, 3'.0, 0'.0, 1'.8.


    Food fight? Enjoy some healthy debate
    in the Yahoo! Answers Food & Drink Q&A. --~--~---------~--~----~------------~-------~--~----~
    To post to this group, send email to NavList@fer3.com
    To unsubscribe, send email to NavList-unsubscribe@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