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
Add Images & Files
    Name or NavList Code:
    Email:
       
    Reply
    Re: Can I Navigate Without an Assumed Position?
    From: Robin Jouan
    Date: 2017 Sep 25, 03:00 -0700

    Dear Antoine, dear All,

    ASTROLAB is a old package (written in BASIC on 1995), and its integrated ephemerids did not pretend to be 0.01 accurate! Most often, I use external ephemerids. But internal ephemerids are convenient for immediate results.

    Thank you for your details about intermediate orbit parameters and precession-nutation values. Certainly, I will check mine when I have time to do so. I think the main differences about GHA & Dec (0.1' order of  magnitude) come from the fact that ASTROLAB is accurate for Aries, but its background sky is shot at a given date, and updated only every 5 years. It was possible to improve it, but users told me that they like to use it as it was (only 450 kBytes with data base and documentation).

    The most important for me is the sight reduction method, without any AP, and that is the reason why I answered to Ron's problem using his GHA+Dec own pairs. So results do agree, obviously.

    Now, I am working about satellites + landmarks direct hybridation, using Matlab for allgorithmics validation. The question of celestial ephemerids is no longer addressed.

    BR, Yves

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    NavList is a community devoted to the preservation and practice of celestial navigation and other methods of traditional position-finding. We're a group of navigators, navigation enthusiasts and hobbyists, mathematicians and physicists, and historians interested in all aspects of navigation but primarily those techniques which are non-electronic.

    To post a message, if you are already signed up as a NavList member, start a new discussion or reply to any posted message and use your posting code (this is a simple low-security password assigned when you join). You may also join by posting. Your first on-topic messsage automatically makes you a member, and a posting code will be assigned and emailed to you for future posts.

    Uniquely, the NavList message boards also permit full interaction entirely by email. You can optionally receive individual posts or daily digests by email, and any member can post messages by email (bypassing the web site) by sending to our posting address which is "NavList@NavList.net". This functionality is similar to a traditional Internet mailing list: post by email, read by email, reply by email. Most members will prefer the web interface here for posting and replying to messages.

    NavList is more than an online community... more about that another day.

    © Copyright notice: please note that the rights to all messages and posts in this discussion group are held by their respective authors. No messages or text or images extracted from messages may be reproduced without the explicit consent of the message author. Email me, Frank Reed, if you have any questions.

    Join / Get NavList ID Code

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    A NavList ID Code guarantees your identity in NavList posts and allows faster posting of messages.

    Retrieve a NavList ID Code

    Enter the email address associated with your NavList messages. Your NavList code will be emailed to you immediately.
    Email:

    Email Settings

    NavList ID 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