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: Differential lunars
    From: Frank Reed
    Date: 2013 Jul 31, 09:37 -0700


    This is a great idea. I think I would call it "on-the-fly calibration" or something like that. When I first saw your phrase "differential lunars", this was not what I was expecting!

    I think we can assume that all sextants are capable of measuring angles and the only thing in question is index error and arc error. Assuming that the lunar we are trying to measure does not sit right at a major change in arc error for the sextant we're using, then we could probably relax the constraints on keeping the star-star test angle right close to the desired lunar. For example, if I observe a star-star angle that's two degrees below the expected lunar and maybe another that's two degrees above the expected lunar and then shoot the lunar in between, I can expect to cancel out the index and arc errors at least as far as I can trust star-star angles (which is another can o' worms). If I'm up in the wee hours in the next few days (waning Moon), I will certainly try this out. Thanks for the idea!


    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